NCR5380.c 71.8 KB
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/* 
 * 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
 */

/*
 * Revision 1.10 1998/9/2	Alan Cox
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 *				(alan@lxorguk.ukuu.org.uk)
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 * Fixed up the timer lockups reported so far. Things still suck. Looking 
 * forward to 2.3 and per device request queues. Then it'll be possible to
 * SMP thread this beast and improve life no end.
 
 * Revision 1.9  1997/7/27	Ronald van Cuijlenborg
 *				(ronald.van.cuijlenborg@tip.nl or nutty@dds.nl)
 * (hopefully) fixed and enhanced USLEEP
 * added support for DTC3181E card (for Mustek scanner)
 *

 * Revision 1.8			Ingmar Baumgart
 *				(ingmar@gonzo.schwaben.de)
 * added support for NCR53C400a card
 *

 * Revision 1.7  1996/3/2       Ray Van Tassle (rayvt@comm.mot.com)
 * added proc_info
 * added support needed for DTC 3180/3280
 * fixed a couple of bugs
 *

 * Revision 1.5  1994/01/19  09:14:57  drew
 * Fixed udelay() hack that was being used on DATAOUT phases
 * instead of a proper wait for the final handshake.
 *
 * Revision 1.4  1994/01/19  06:44:25  drew
 * *** empty log message ***
 *
 * Revision 1.3  1994/01/19  05:24:40  drew
 * Added support for TCR LAST_BYTE_SENT bit.
 *
 * Revision 1.2  1994/01/15  06:14:11  drew
 * REAL DMA support, bug fixes.
 *
 * Revision 1.1  1994/01/15  06:00:54  drew
 * Initial revision
 *
 */

/*
 * Further development / testing that should be done : 
 * 1.  Cleanup the NCR5380_transfer_dma function and DMA operation complete
 *     code so that everything does the same thing that's done at the 
 *     end of a pseudo-DMA read operation.
 *
 * 2.  Fix REAL_DMA (interrupt driven, polled works fine) -
 *     basically, transfer size needs to be reduced by one 
 *     and the last byte read as is done with PSEUDO_DMA.
 * 
 * 4.  Test SCSI-II tagged queueing (I have no devices which support 
 *      tagged queueing)
 */

#ifndef notyet
#undef REAL_DMA
#endif

#ifdef BOARD_REQUIRES_NO_DELAY
#define io_recovery_delay(x)
#else
#define io_recovery_delay(x)	udelay(x)
#endif

/*
 * 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.
 *
 * (Note from hch:  unfortunately it was not enough for the different
 * m68k folks and instead of improving this driver they copied it
 * and hacked it up for their needs.  As a consequence they lost
 * most updates to this driver.  Maybe someone will fix all these
 * drivers to use a common core one day..)
 *
 * 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 
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 * while doing long seek operations. [...] These
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 * 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.
 *
 * SCSI pointers are maintained in the SCp field of SCSI command 
 * structures, being 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 control options : 
 * AUTOPROBE_IRQ - if defined, the NCR5380_probe_irq() function will be 
 *      defined.
 * 
 * AUTOSENSE - if defined, REQUEST SENSE will be performed automatically
 *      for commands that return with a CHECK CONDITION status. 
 *
 * DIFFERENTIAL - if defined, NCR53c81 chips will use external differential
 *      transceivers. 
 *
 * DONT_USE_INTR - if defined, never use interrupts, even if we probe or
 *      override-configure an IRQ.
 *
 * PSEUDO_DMA - if defined, PSEUDO DMA is used during the data transfer phases.
 *
 * REAL_DMA - if defined, REAL DMA is used during the data transfer phases.
 *
 * REAL_DMA_POLL - if defined, REAL DMA is used but the driver doesn't
 *      rely on phase mismatch and EOP interrupts to determine end 
 *      of phase.
 *
 * Defaults for these will be provided although the user may want to adjust 
 * these to allocate CPU resources to the SCSI driver or "real" code.
 * 
 * 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
 * REAL functions : 
 * NCR5380_REAL_DMA should be defined if real DMA is to be used.
 * Note that the DMA setup functions should return the number of bytes 
 *      that they were able to program the controller for.
 *
 * Also note that generic i386/PC versions of these macros are 
 *      available as NCR5380_i386_dma_write_setup,
 *      NCR5380_i386_dma_read_setup, and NCR5380_i386_dma_residual.
 *
 * NCR5380_dma_write_setup(instance, src, count) - initialize
 * NCR5380_dma_read_setup(instance, dst, count) - initialize
 * NCR5380_dma_residual(instance); - residual count
 *
 * PSEUDO functions :
 * NCR5380_pwrite(instance, src, count)
 * NCR5380_pread(instance, dst, count);
 *
 * The generic driver is initialized by calling NCR5380_init(instance),
 * after setting the appropriate host specific fields and ID.  If the 
 * driver wishes to autoprobe for an IRQ line, the NCR5380_probe_irq(instance,
 * possible) function may be used.
 */

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static int do_abort(struct Scsi_Host *);
static void do_reset(struct Scsi_Host *);
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/*
 *	initialize_SCp		-	init the scsi pointer field
 *	@cmd: command block to set up
 *
 *	Set up the internal fields in the SCSI command.
 */

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static inline void initialize_SCp(struct scsi_cmnd *cmd)
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{
	/* 
	 * Initialize the Scsi Pointer field so that all of the commands in the 
	 * various queues are valid.
	 */

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	if (scsi_bufflen(cmd)) {
		cmd->SCp.buffer = scsi_sglist(cmd);
		cmd->SCp.buffers_residual = scsi_sg_count(cmd) - 1;
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		cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
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		cmd->SCp.this_residual = cmd->SCp.buffer->length;
	} else {
		cmd->SCp.buffer = NULL;
		cmd->SCp.buffers_residual = 0;
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		cmd->SCp.ptr = NULL;
		cmd->SCp.this_residual = 0;
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	}
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	cmd->SCp.Status = 0;
	cmd->SCp.Message = 0;
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}

/**
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 * NCR5380_poll_politely2 - wait for two chip register values
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 * @instance: controller to poll
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 * @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
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 * @wait: Time-out in jiffies
 *
 * 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.
 *
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 * Returns 0 if either or both event(s) occurred otherwise -ETIMEDOUT.
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 */
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static int NCR5380_poll_politely2(struct Scsi_Host *instance,
                                  int reg1, int bit1, int val1,
                                  int reg2, int bit2, int val2, int wait)
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{
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	struct NCR5380_hostdata *hostdata = shost_priv(instance);
	unsigned long deadline = jiffies + wait;
	unsigned long n;

	/* Busy-wait for up to 10 ms */
	n = min(10000U, jiffies_to_usecs(wait));
	n *= hostdata->accesses_per_ms;
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	n /= 2000;
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	do {
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		if ((NCR5380_read(reg1) & bit1) == val1)
			return 0;
		if ((NCR5380_read(reg2) & bit2) == val2)
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			return 0;
		cpu_relax();
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	} while (n--);

	if (irqs_disabled() || in_interrupt())
		return -ETIMEDOUT;

	/* Repeatedly sleep for 1 ms until deadline */
	while (time_is_after_jiffies(deadline)) {
		schedule_timeout_uninterruptible(1);
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		if ((NCR5380_read(reg1) & bit1) == val1)
			return 0;
		if ((NCR5380_read(reg2) & bit2) == val2)
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			return 0;
	}
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	return -ETIMEDOUT;
}

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static inline int NCR5380_poll_politely(struct Scsi_Host *instance,
                                        int reg, int bit, int val, int wait)
{
	return NCR5380_poll_politely2(instance, reg, bit, val,
	                                        reg, bit, val, wait);
}

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static struct {
	unsigned char value;
	const char *name;
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} phases[] __maybe_unused = {
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	{PHASE_DATAOUT, "DATAOUT"}, 
	{PHASE_DATAIN, "DATAIN"}, 
	{PHASE_CMDOUT, "CMDOUT"}, 
	{PHASE_STATIN, "STATIN"}, 
	{PHASE_MSGOUT, "MSGOUT"}, 
	{PHASE_MSGIN, "MSGIN"}, 
	{PHASE_UNKNOWN, "UNKNOWN"}
};

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#if NDEBUG
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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_ATN, "ATN"}, 
	{BASR_ACK, "ACK"}, 
	{0, NULL}
}, 
icrs[] = { 
	{ICR_ASSERT_RST, "ASSERT RST"}, 
	{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, "MODE BLOCK DMA"}, 
	{MR_TARGET, "MODE TARGET"}, 
	{MR_ENABLE_PAR_CHECK, "MODE PARITY CHECK"}, 
	{MR_ENABLE_PAR_INTR, "MODE PARITY INTR"}, 
	{MR_MONITOR_BSY, "MODE MONITOR BSY"}, 
	{MR_DMA_MODE, "MODE DMA"}, 
	{MR_ARBITRATE, "MODE ARBITRATION"}, 
	{0, NULL}
};

/**
 *	NCR5380_print	-	print scsi bus signals
 *	@instance:	adapter state to dump
 *
 *	Print the SCSI bus signals for debugging purposes
 *
 *	Locks: caller holds hostdata lock (not essential)
 */

static void NCR5380_print(struct Scsi_Host *instance)
{
	unsigned char status, data, basr, mr, icr, i;

	data = NCR5380_read(CURRENT_SCSI_DATA_REG);
	status = NCR5380_read(STATUS_REG);
	mr = NCR5380_read(MODE_REG);
	icr = NCR5380_read(INITIATOR_COMMAND_REG);
	basr = NCR5380_read(BUS_AND_STATUS_REG);

	printk("STATUS_REG: %02x ", status);
	for (i = 0; signals[i].mask; ++i)
		if (status & signals[i].mask)
			printk(",%s", signals[i].name);
	printk("\nBASR: %02x ", basr);
	for (i = 0; basrs[i].mask; ++i)
		if (basr & basrs[i].mask)
			printk(",%s", basrs[i].name);
	printk("\nICR: %02x ", icr);
	for (i = 0; icrs[i].mask; ++i)
		if (icr & icrs[i].mask)
			printk(",%s", icrs[i].name);
	printk("\nMODE: %02x ", mr);
	for (i = 0; mrs[i].mask; ++i)
		if (mr & mrs[i].mask)
			printk(",%s", mrs[i].name);
	printk("\n");
}


/* 
 *	NCR5380_print_phase	-	show SCSI phase
 *	@instance: adapter to dump
 *
 * 	Print the current SCSI phase for debugging purposes
 *
 *	Locks: none
 */

static void NCR5380_print_phase(struct Scsi_Host *instance)
{
	unsigned char status;
	int i;

	status = NCR5380_read(STATUS_REG);
	if (!(status & SR_REQ))
		printk("scsi%d : REQ not asserted, phase unknown.\n", instance->host_no);
	else {
		for (i = 0; (phases[i].value != PHASE_UNKNOWN) && (phases[i].value != (status & PHASE_MASK)); ++i);
		printk("scsi%d : phase %s\n", instance->host_no, phases[i].name);
	}
}
#endif


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static int probe_irq __initdata;
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/**
 *	probe_intr	-	helper for IRQ autoprobe
 *	@irq: interrupt number
 *	@dev_id: unused
 *	@regs: unused
 *
 *	Set a flag to indicate the IRQ in question was received. This is
 *	used by the IRQ probe code.
 */
 
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static irqreturn_t __init probe_intr(int irq, void *dev_id)
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{
	probe_irq = irq;
	return IRQ_HANDLED;
}

/**
 *	NCR5380_probe_irq	-	find the IRQ of an NCR5380
 *	@instance: NCR5380 controller
 *	@possible: bitmask of ISA IRQ lines
 *
 *	Autoprobe for the IRQ line used by the NCR5380 by triggering an IRQ
 *	and then looking to see what interrupt actually turned up.
 *
 *	Locks: none, irqs must be enabled on entry
 */

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static int __init __maybe_unused NCR5380_probe_irq(struct Scsi_Host *instance,
						int possible)
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{
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	struct NCR5380_hostdata *hostdata = shost_priv(instance);
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	unsigned long timeout;
	int trying_irqs, i, mask;

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	for (trying_irqs = 0, i = 1, mask = 2; i < 16; ++i, mask <<= 1)
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		if ((mask & possible) && (request_irq(i, &probe_intr, 0, "NCR-probe", NULL) == 0))
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			trying_irqs |= mask;

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	timeout = jiffies + msecs_to_jiffies(250);
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	probe_irq = NO_IRQ;
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	/*
	 * A interrupt is triggered whenever BSY = false, SEL = true
	 * and a bit set in the SELECT_ENABLE_REG is asserted on the 
	 * SCSI bus.
	 *
	 * Note that the bus is only driven when the phase control signals
	 * (I/O, C/D, and MSG) match those in the TCR, so we must reset that
	 * to zero.
	 */

	NCR5380_write(TARGET_COMMAND_REG, 0);
	NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
	NCR5380_write(OUTPUT_DATA_REG, hostdata->id_mask);
	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_DATA | ICR_ASSERT_SEL);

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	while (probe_irq == NO_IRQ && time_before(jiffies, timeout))
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		schedule_timeout_uninterruptible(1);
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	NCR5380_write(SELECT_ENABLE_REG, 0);
	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);

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	for (i = 1, mask = 2; i < 16; ++i, mask <<= 1)
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		if (trying_irqs & mask)
			free_irq(i, NULL);

	return probe_irq;
}

/**
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 *	NCR58380_info - report driver and host information
 *	@instance: relevant scsi host instance
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 *
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 *	For use as the host template info() handler.
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 *
 *	Locks: none
 */

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static const char *NCR5380_info(struct Scsi_Host *instance)
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{
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	struct NCR5380_hostdata *hostdata = shost_priv(instance);

	return hostdata->info;
}

static void prepare_info(struct Scsi_Host *instance)
{
	struct NCR5380_hostdata *hostdata = shost_priv(instance);

	snprintf(hostdata->info, sizeof(hostdata->info),
	         "%s, io_port 0x%lx, n_io_port %d, "
	         "base 0x%lx, irq %d, "
	         "can_queue %d, cmd_per_lun %d, "
	         "sg_tablesize %d, this_id %d, "
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	         "flags { %s%s%s}, "
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	         "options { %s} ",
	         instance->hostt->name, instance->io_port, instance->n_io_port,
	         instance->base, instance->irq,
	         instance->can_queue, instance->cmd_per_lun,
	         instance->sg_tablesize, instance->this_id,
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	         hostdata->flags & FLAG_NO_DMA_FIXUP  ? "NO_DMA_FIXUP "  : "",
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	         hostdata->flags & FLAG_NO_PSEUDO_DMA ? "NO_PSEUDO_DMA " : "",
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	         hostdata->flags & FLAG_TOSHIBA_DELAY ? "TOSHIBA_DELAY "  : "",
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#ifdef AUTOPROBE_IRQ
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	         "AUTOPROBE_IRQ "
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#endif
#ifdef DIFFERENTIAL
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	         "DIFFERENTIAL "
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#endif
#ifdef REAL_DMA
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	         "REAL_DMA "
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#endif
#ifdef REAL_DMA_POLL
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	         "REAL_DMA_POLL "
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#endif
#ifdef PARITY
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	         "PARITY "
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#endif
#ifdef PSEUDO_DMA
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	         "PSEUDO_DMA "
#endif
	         "");
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}

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#ifdef PSEUDO_DMA
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/******************************************/
/*
 * /proc/scsi/[dtc pas16 t128 generic]/[0-ASC_NUM_BOARD_SUPPORTED]
 *
 * *buffer: I/O buffer
 * **start: if inout == FALSE pointer into buffer where user read should start
 * offset: current offset
 * length: length of buffer
 * hostno: Scsi_Host host_no
 * inout: TRUE - user is writing; FALSE - user is reading
 *
 * Return the number of bytes read from or written
 */

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static int __maybe_unused NCR5380_write_info(struct Scsi_Host *instance,
	char *buffer, int length)
{
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	struct NCR5380_hostdata *hostdata = shost_priv(instance);

	hostdata->spin_max_r = 0;
	hostdata->spin_max_w = 0;
	return 0;
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}
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static int __maybe_unused NCR5380_show_info(struct seq_file *m,
	struct Scsi_Host *instance)
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{
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	struct NCR5380_hostdata *hostdata = shost_priv(instance);
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	seq_printf(m, "Highwater I/O busy spin counts: write %d, read %d\n",
587
	        hostdata->spin_max_w, hostdata->spin_max_r);
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	return 0;
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}
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#endif
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/**
 *	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
 *
 *	Locks: interrupts must be enabled when we are called 
 */

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static int NCR5380_init(struct Scsi_Host *instance, int flags)
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{
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	struct NCR5380_hostdata *hostdata = shost_priv(instance);
611
	int i;
612
	unsigned long deadline;
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	if(in_interrupt())
		printk(KERN_ERR "NCR5380_init called with interrupts off!\n");

	hostdata->id_mask = 1 << instance->this_id;
	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;
#ifdef REAL_DMA
	hostdata->dmalen = 0;
#endif
626
	spin_lock_init(&hostdata->lock);
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	hostdata->connected = NULL;
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	hostdata->sensing = NULL;
	INIT_LIST_HEAD(&hostdata->autosense);
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	INIT_LIST_HEAD(&hostdata->unissued);
	INIT_LIST_HEAD(&hostdata->disconnected);

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	hostdata->flags = flags;
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	INIT_WORK(&hostdata->main_task, NCR5380_main);
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	hostdata->work_q = alloc_workqueue("ncr5380_%d",
	                        WQ_UNBOUND | WQ_MEM_RECLAIM,
	                        1, instance->host_no);
	if (!hostdata->work_q)
		return -ENOMEM;

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	hostdata->host = instance;

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	prepare_info(instance);

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	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);
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	/* 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));
	hostdata->accesses_per_ms = i / 256;

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	return 0;
}
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/**
 * 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)
{
684
	struct NCR5380_hostdata *hostdata = shost_priv(instance);
685
	int pass;
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	for (pass = 1; (NCR5380_read(STATUS_REG) & SR_BSY) && pass <= 6; ++pass) {
		switch (pass) {
		case 1:
		case 3:
		case 5:
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			shost_printk(KERN_ERR, instance, "SCSI bus busy, waiting up to five seconds\n");
			NCR5380_poll_politely(instance,
			                      STATUS_REG, SR_BSY, 0, 5 * HZ);
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			break;
		case 2:
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			shost_printk(KERN_ERR, instance, "bus busy, attempting abort\n");
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			do_abort(instance);
			break;
		case 4:
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			shost_printk(KERN_ERR, instance, "bus busy, attempting reset\n");
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			do_reset(instance);
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			/* 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);
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			break;
		case 6:
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			shost_printk(KERN_ERR, instance, "bus locked solid\n");
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			return -ENXIO;
		}
	}
	return 0;
}

/**
 *	NCR5380_exit	-	remove an NCR5380
 *	@instance: adapter to remove
 */

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static void NCR5380_exit(struct Scsi_Host *instance)
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{
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	struct NCR5380_hostdata *hostdata = shost_priv(instance);
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	cancel_work_sync(&hostdata->main_task);
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	destroy_workqueue(hostdata->work_q);
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}

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/**
 * 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);

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	if (hostdata->sensing == cmd) {
		/* Autosense processing ends here */
		if ((cmd->result & 0xff) != SAM_STAT_GOOD) {
			scsi_eh_restore_cmnd(cmd, &hostdata->ses);
			set_host_byte(cmd, DID_ERROR);
		} else
			scsi_eh_restore_cmnd(cmd, &hostdata->ses);
		hostdata->sensing = NULL;
	}

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	hostdata->busy[scmd_id(cmd)] &= ~(1 << cmd->device->lun);

	cmd->scsi_done(cmd);
}

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/**
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 * NCR5380_queue_command - queue a command
 * @instance: the relevant SCSI adapter
 * @cmd: SCSI command
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 *
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 * 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.
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 */

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static int NCR5380_queue_command(struct Scsi_Host *instance,
                                 struct scsi_cmnd *cmd)
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{
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	struct NCR5380_hostdata *hostdata = shost_priv(instance);
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	struct NCR5380_cmd *ncmd = scsi_cmd_priv(cmd);
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	unsigned long flags;
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#if (NDEBUG & NDEBUG_NO_WRITE)
	switch (cmd->cmnd[0]) {
	case WRITE_6:
	case WRITE_10:
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		shost_printk(KERN_DEBUG, instance, "WRITE attempted with NDEBUG_NO_WRITE set\n");
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		cmd->result = (DID_ERROR << 16);
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		cmd->scsi_done(cmd);
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		return 0;
	}
#endif				/* (NDEBUG & NDEBUG_NO_WRITE) */

	cmd->result = 0;

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	spin_lock_irqsave(&hostdata->lock, flags);
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	/* 
	 * 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.
	 */

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	if (cmd->cmnd[0] == REQUEST_SENSE)
		list_add(&ncmd->list, &hostdata->unissued);
	else
		list_add_tail(&ncmd->list, &hostdata->unissued);

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	spin_unlock_irqrestore(&hostdata->lock, flags);
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	dsprintk(NDEBUG_QUEUES, instance, "command %p added to %s of queue\n",
	         cmd, (cmd->cmnd[0] == REQUEST_SENSE) ? "head" : "tail");
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	/* Kick off command processing */
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	queue_work(hostdata->work_q, &hostdata->main_task);
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	return 0;
}

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/**
 * 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 (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 = scsi_cmd_priv(cmd);

	if (hostdata->sensing) {
		scsi_eh_restore_cmnd(cmd, &hostdata->ses);
		list_add(&ncmd->list, &hostdata->autosense);
		hostdata->sensing = NULL;
	} else
		list_add(&ncmd->list, &hostdata->unissued);
}

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/**
 *	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.
 * 
 *	Locks: called as its own thread with no locks held. Takes the
 *	host lock and called routines may take the isa dma lock.
 */

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static void NCR5380_main(struct work_struct *work)
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{
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	struct NCR5380_hostdata *hostdata =
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		container_of(work, struct NCR5380_hostdata, main_task);
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	struct Scsi_Host *instance = hostdata->host;
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	struct scsi_cmnd *cmd;
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	int done;
	
893
	spin_lock_irq(&hostdata->lock);
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	do {
		done = 1;
896

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		while (!hostdata->connected &&
		       (cmd = dequeue_next_cmd(instance))) {
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			dsprintk(NDEBUG_MAIN, instance, "main: dequeued %p\n", cmd);
901

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			/*
			 * 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.
			 */
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			if (!NCR5380_select(instance, cmd)) {
				dsprintk(NDEBUG_MAIN, instance, "main: selected target %d for command %p\n",
				         scmd_id(cmd), cmd);
			} else {
				dsprintk(NDEBUG_MAIN | NDEBUG_QUEUES, instance,
				         "main: select failed, returning %p to queue\n", cmd);
				requeue_cmd(instance, cmd);
			}
		}
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		if (hostdata->connected
#ifdef REAL_DMA
		    && !hostdata->dmalen
#endif
		    ) {
929
			dprintk(NDEBUG_MAIN, "scsi%d : main() : performing information transfer\n", instance->host_no);
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			NCR5380_information_transfer(instance);
931
			dprintk(NDEBUG_MAIN, "scsi%d : main() : done set false\n", instance->host_no);
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			done = 0;
933
		}
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	} while (!done);
935
	spin_unlock_irq(&hostdata->lock);
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}

#ifndef DONT_USE_INTR

/**
941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971
 * 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.
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 */

974
static irqreturn_t NCR5380_intr(int irq, void *dev_id)
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{
976
	struct Scsi_Host *instance = dev_id;
977 978
	struct NCR5380_hostdata *hostdata = shost_priv(instance);
	int handled = 0;
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	unsigned char basr;
	unsigned long flags;

982
	spin_lock_irqsave(&hostdata->lock, flags);
983 984 985 986 987 988 989 990

	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);

		dprintk(NDEBUG_INTR, "scsi%d: IRQ %d, BASR 0x%02x, SR 0x%02x, MR 0x%02x\n",
		        instance->host_no, irq, basr, sr, mr);
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#if defined(REAL_DMA)
993 994 995 996 997
		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.
			 */
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999
			dprintk(NDEBUG_INTR, "scsi%d: interrupt in DMA mode\n", intance->host_no);
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1001
			int transferred;
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1003 1004 1005
			if (!hostdata->connected)
				panic("scsi%d : DMA interrupt with no connected cmd\n",
				      instance->hostno);
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1007 1008 1009 1010
			transferred = hostdata->dmalen - NCR5380_dma_residual(instance);
			hostdata->connected->SCp.this_residual -= transferred;
			hostdata->connected->SCp.ptr += transferred;
			hostdata->dmalen = 0;
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			/* FIXME: we need to poll briefly then defer a workqueue task ! */
			NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG, BASR_ACK, 0, 2 * HZ);

			NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
			NCR5380_write(MODE_REG, MR_BASE);
			NCR5380_read(RESET_PARITY_INTERRUPT_REG);
		} else
#endif /* REAL_DMA */
		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);

			dprintk(NDEBUG_INTR, "scsi%d: interrupt with SEL and IO\n",
			        instance->host_no);

			if (!hostdata->connected) {
				NCR5380_reselect(instance);
				queue_work(hostdata->work_q, &hostdata->main_task);
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			}
1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045
			if (!hostdata->connected)
				NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
		} else {
			/* Probably Bus Reset */
			NCR5380_read(RESET_PARITY_INTERRUPT_REG);

			dprintk(NDEBUG_INTR, "scsi%d: unknown interrupt\n", instance->host_no);
		}
		handled = 1;
	} else {
		shost_printk(KERN_NOTICE, instance, "interrupt without IRQ bit\n");
	}

1046
	spin_unlock_irqrestore(&hostdata->lock, flags);
1047 1048

	return IRQ_RETVAL(handled);
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}

#endif 

/* 
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 * Function : int NCR5380_select(struct Scsi_Host *instance,
 *                               struct scsi_cmnd *cmd)
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 *
 * Purpose : establishes I_T_L or I_T_L_Q nexus for new or existing command,
 *      including ARBITRATION, SELECTION, and initial message out for 
 *      IDENTIFY and queue messages. 
 *
 * Inputs : instance - instantiation of the 5380 driver on which this 
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 *      target lives, cmd - SCSI command to execute.
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 * 
1064 1065 1066
 * Returns : -1 if selection failed but should be retried.
 *      0 if selection failed and should not be retried.
 *      0 if selection succeeded completely (hostdata->connected == cmd).
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 *
 * 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 : I_T_L or I_T_L_Q nexus will be established, 
 *              instance->connected will be set to cmd.  
 *              SELECT interrupt will be disabled.
 *
 *      If failed (no target) : cmd->scsi_done() will be called, and the 
 *              cmd->result host byte set to DID_BAD_TARGET.
 *
 *	Locks: caller holds hostdata lock in IRQ mode
 */
 
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static int NCR5380_select(struct Scsi_Host *instance, struct scsi_cmnd *cmd)
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{
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	struct NCR5380_hostdata *hostdata = shost_priv(instance);
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	unsigned char tmp[3], phase;
	unsigned char *data;
	int len;
	int err;

	NCR5380_dprint(NDEBUG_ARBITRATION, instance);
1093
	dprintk(NDEBUG_ARBITRATION, "scsi%d : starting arbitration, id = %d\n", instance->host_no, instance->this_id);
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	/* 
	 * 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);

1109 1110 1111
	/* The chip now waits for BUS FREE phase. Then after the 800 ns
	 * Bus Free Delay, arbitration will begin.
	 */
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1113
	spin_unlock_irq(&hostdata->lock);
1114 1115 1116
	err = NCR5380_poll_politely2(instance, MODE_REG, MR_ARBITRATE, 0,
	                INITIATOR_COMMAND_REG, ICR_ARBITRATION_PROGRESS,
	                                       ICR_ARBITRATION_PROGRESS, HZ);
1117
	spin_lock_irq(&hostdata->lock);
1118 1119 1120 1121 1122 1123 1124 1125 1126
	if (!(NCR5380_read(MODE_REG) & MR_ARBITRATE)) {
		/* Reselection interrupt */
		return -1;
	}
	if (err < 0) {
		NCR5380_write(MODE_REG, MR_BASE);
		shost_printk(KERN_ERR, instance,
		             "select: arbitration timeout\n");
		return -1;
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	}
1128
	spin_unlock_irq(&hostdata->lock);
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1129

1130
	/* The SCSI-2 arbitration delay is 2.4 us */
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	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);
1136
		dprintk(NDEBUG_ARBITRATION, "scsi%d : lost arbitration, deasserting MR_ARBITRATE\n", instance->host_no);
1137
		spin_lock_irq(&hostdata->lock);
1138
		return -1;
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	}
1140 1141 1142 1143 1144 1145 1146

	/* 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);
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	/* 
	 * Again, bus clear + bus settle time is 1.2us, however, this is 
	 * a minimum so we'll udelay ceil(1.2)
	 */

1153 1154 1155 1156
	if (hostdata->flags & FLAG_TOSHIBA_DELAY)
		udelay(15);
	else
		udelay(2);
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1158 1159
	spin_lock_irq(&hostdata->lock);

1160 1161 1162 1163
	/* NCR5380_reselect() clears MODE_REG after a reselection interrupt */
	if (!(NCR5380_read(MODE_REG) & MR_ARBITRATE))
		return -1;

1164
	dprintk(NDEBUG_ARBITRATION, "scsi%d : won arbitration\n", instance->host_no);
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	/* 
	 * Now that we have won arbitration, start Selection process, asserting 
	 * the host and target ID's on the SCSI bus.
	 */

1171
	NCR5380_write(OUTPUT_DATA_REG, (hostdata->id_mask | (1 << scmd_id(cmd))));
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	/* 
	 * 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);

1188 1189
	spin_unlock_irq(&hostdata->lock);

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	/*
	 * 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);

1218
	dprintk(NDEBUG_SELECTION, "scsi%d : selecting target %d\n", instance->host_no, scmd_id(cmd));
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	/* 
	 * The SCSI specification calls for a 250 ms timeout for the actual 
	 * selection.
	 */

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	err = NCR5380_poll_politely(instance, STATUS_REG, SR_BSY, SR_BSY,
	                            msecs_to_jiffies(250));
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	if ((NCR5380_read(STATUS_REG) & (SR_SEL | SR_IO)) == (SR_SEL | SR_IO)) {
1229
		spin_lock_irq(&hostdata->lock);
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		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
		NCR5380_reselect(instance);
1232 1233
		if (!hostdata->connected)
			NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
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		printk("scsi%d : reselection after won arbitration?\n", instance->host_no);
		return -1;
	}
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	if (err < 0) {
1239
		spin_lock_irq(&hostdata->lock);
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		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
		cmd->result = DID_BAD_TARGET << 16;
1242
		complete_cmd(instance, cmd);
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		NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
		dprintk(NDEBUG_SELECTION, "scsi%d : target did not respond within 250ms\n",
		        instance->host_no);
		return 0;
	}

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	/* 
	 * 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.
	 * 
	 * If SCSI-II tagged queuing is enabled, we also send a SIMPLE_QUEUE_TAG
	 * message (2 bytes) with a tag ID that we increment with every command
	 * until it wraps back to 0.
	 *
	 * XXX - it turns out that there are some broken SCSI-II devices,
	 *       which claim to support tagged queuing but fail when more than
	 *       some number of commands are issued at once.
	 */

	/* Wait for start of REQ/ACK handshake */

	err = NCR5380_poll_politely(instance, STATUS_REG, SR_REQ, SR_REQ, HZ);
1277
	spin_lock_irq(&hostdata->lock);
1278
	if (err < 0) {
1279 1280
		shost_printk(KERN_ERR, instance, "select: REQ timeout\n");
		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
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		NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
1282
		return -1;
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	}

1285
	dprintk(NDEBUG_SELECTION, "scsi%d : target %d selected, going into MESSAGE OUT phase.\n", instance->host_no, cmd->device->id);
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	tmp[0] = IDENTIFY(((instance->irq == NO_IRQ) ? 0 : 1), cmd->device->lun);
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	len = 1;
	cmd->tag = 0;

	/* Send message(s) */
	data = tmp;
	phase = PHASE_MSGOUT;
	NCR5380_transfer_pio(instance, &phase, &len, &data);
1295
	dprintk(NDEBUG_SELECTION, "scsi%d : nexus established.\n", instance->host_no);
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1296
	/* XXX need to handle errors here */
1297

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	hostdata->connected = cmd;
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	hostdata->busy[cmd->device->id] |= (1 << (cmd->device->lun & 0xFF));
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1301
	initialize_SCp(cmd);
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	return 0;
}

/* 
 * 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.
 * 
 * Returns : -1 when different phase is entered without transferring
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 *      maximum number of bytes, 0 if all bytes or transferred or exit
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 *      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 char p = *phase, tmp;
	int c = *count;
	unsigned char *d = *data;

	if (!(p & SR_IO))
1337
		dprintk(NDEBUG_PIO, "scsi%d : pio write %d bytes\n", instance->host_no, c);
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	else
1339
		dprintk(NDEBUG_PIO, "scsi%d : pio read %d bytes\n", instance->host_no, c);
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	/* 
	 * 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 
		 */

1355
		if (NCR5380_poll_politely(instance, STATUS_REG, SR_REQ, SR_REQ, HZ) < 0)
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1356 1357
			break;

1358
		dprintk(NDEBUG_HANDSHAKE, "scsi%d : REQ detected\n", instance->host_no);
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1359 1360

		/* Check for phase mismatch */
1361
		if ((NCR5380_read(STATUS_REG) & PHASE_MASK) != p) {
1362
			dprintk(NDEBUG_HANDSHAKE, "scsi%d : phase mismatch\n", instance->host_no);
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			NCR5380_dprint_phase(NDEBUG_HANDSHAKE, 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);
		}

1396 1397 1398 1399
		if (NCR5380_poll_politely(instance,
		                          STATUS_REG, SR_REQ, 0, 5 * HZ) < 0)
			break;

1400
		dprintk(NDEBUG_HANDSHAKE, "scsi%d : req false, handshake complete\n", instance->host_no);
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/*
 * 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);

1421
	dprintk(NDEBUG_PIO, "scsi%d : residual %d\n", instance->host_no, c);
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1422 1423 1424 1425

	*count = c;
	*data = d;
	tmp = NCR5380_read(STATUS_REG);
1426 1427 1428 1429 1430
	/* 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))
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1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441
		*phase = tmp & PHASE_MASK;
	else
		*phase = PHASE_UNKNOWN;

	if (!c || (*phase == p))
		return 0;
	else
		return -1;
}

/**
1442 1443
 * do_reset - issue a reset command
 * @instance: adapter to reset
L
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1444
 *
1445 1446
 * Issue a reset sequence to the NCR5380 and try and get the bus
 * back into sane shape.
L
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1447
 *
1448 1449 1450
 * 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.
L
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1451 1452
 */
 
1453 1454
static void do_reset(struct Scsi_Host *instance)
{
1455 1456 1457 1458 1459
	unsigned long flags;

	local_irq_save(flags);
	NCR5380_write(TARGET_COMMAND_REG,
	              PHASE_SR_TO_TCR(NCR5380_read(STATUS_REG) & PHASE_MASK));
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	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_RST);
1461
	udelay(50);
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	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
1463 1464
	(void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
	local_irq_restore(flags);
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}

1467 1468 1469 1470
/**
 * do_abort - abort the currently established nexus by going to
 * MESSAGE OUT phase and sending an ABORT message.
 * @instance: relevant scsi host instance
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 *
1472
 * Returns 0 on success, -1 on failure.
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 */

1475 1476
static int do_abort(struct Scsi_Host *instance)
{
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	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.
	 */

1494
	rc = NCR5380_poll_politely(instance, STATUS_REG, SR_REQ, SR_REQ, 10 * HZ);
1495
	if (rc < 0)
1496
		goto timeout;
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1498
	tmp = NCR5380_read(STATUS_REG) & PHASE_MASK;
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	NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(tmp));

1502
	if (tmp != PHASE_MSGOUT) {
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		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN | ICR_ASSERT_ACK);
1504
		rc = NCR5380_poll_politely(instance, STATUS_REG, SR_REQ, 0, 3 * HZ);
1505
		if (rc < 0)
1506 1507
			goto timeout;
		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
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	}
	tmp = ABORT;
	msgptr = &tmp;
	len = 1;
	phase = PHASE_MSGOUT;
1513
	NCR5380_transfer_pio(instance, &phase, &len, &msgptr);
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	/*
	 * If we got here, and the command completed successfully,
	 * we're about to go into bus free state.
	 */

	return len ? -1 : 0;
1521 1522 1523 1524

timeout:
	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
	return -1;
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}

#if defined(REAL_DMA) || defined(PSEUDO_DMA) || defined (REAL_DMA_POLL)
/* 
 * 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
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 *      maximum number of bytes, 0 if all bytes or transferred or exit
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 *      is in same phase.
 *
 *      Also, *phase, *count, *data are modified in place.
 *
 *	Locks: io_request lock held by caller
 */


static int NCR5380_transfer_dma(struct Scsi_Host *instance, unsigned char *phase, int *count, unsigned char **data) {
	register int c = *count;
	register unsigned char p = *phase;
	register unsigned char *d = *data;
	unsigned char tmp;
	int foo;
#if defined(REAL_DMA_POLL)
	int cnt, toPIO;
	unsigned char saved_data = 0, overrun = 0, residue;
#endif

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1560
	struct NCR5380_hostdata *hostdata = shost_priv(instance);
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	if ((tmp = (NCR5380_read(STATUS_REG) & PHASE_MASK)) != p) {
		*phase = tmp;
		return -1;
	}
#if defined(REAL_DMA) || defined(REAL_DMA_POLL)
	if (p & SR_IO) {
1568 1569
		if (!(hostdata->flags & FLAG_NO_DMA_FIXUPS))
			c -= 2;
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	}
1571
	dprintk(NDEBUG_DMA, "scsi%d : initializing DMA channel %d for %s, %d bytes %s %0x\n", instance->host_no, instance->dma_channel, (p & SR_IO) ? "reading" : "writing", c, (p & SR_IO) ? "to" : "from", (unsigned) d);
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	hostdata->dma_len = (p & SR_IO) ? NCR5380_dma_read_setup(instance, d, c) : NCR5380_dma_write_setup(instance, d, c);
#endif

	NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(p));

#ifdef REAL_DMA
1578 1579
	NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE | MR_MONITOR_BSY |
	                        MR_ENABLE_EOP_INTR);
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#elif defined(REAL_DMA_POLL)
1581
	NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE | MR_MONITOR_BSY);
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#else
	/*
	 * Note : on my sample board, watch-dog timeouts occurred when interrupts
	 * were not disabled for the duration of a single DMA transfer, from 
	 * before the setting of DMA mode to after transfer of the last byte.
	 */

1589
	if (hostdata->flags & FLAG_NO_DMA_FIXUP)
1590 1591
		NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE | MR_MONITOR_BSY |
		                        MR_ENABLE_EOP_INTR);
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	else
1593
		NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE | MR_MONITOR_BSY);
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#endif				/* def REAL_DMA */

1596
	dprintk(NDEBUG_DMA, "scsi%d : mode reg = 0x%X\n", instance->host_no, NCR5380_read(MODE_REG));
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	/* 
	 *	On the PAS16 at least I/O recovery delays are not needed here.
	 *	Everyone else seems to want them.
	 */

	if (p & SR_IO) {
		io_recovery_delay(1);
		NCR5380_write(START_DMA_INITIATOR_RECEIVE_REG, 0);
	} else {
		io_recovery_delay(1);
		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_DATA);
		io_recovery_delay(1);
		NCR5380_write(START_DMA_SEND_REG, 0);
		io_recovery_delay(1);
	}

#if defined(REAL_DMA_POLL)
	do {
		tmp = NCR5380_read(BUS_AND_STATUS_REG);
	} while ((tmp & BASR_PHASE_MATCH) && !(tmp & (BASR_BUSY_ERROR | BASR_END_DMA_TRANSFER)));

/*
   At this point, either we've completed DMA, or we have a phase mismatch,
   or we've unexpectedly lost BUSY (which is a real error).

   For write DMAs, 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-writes
   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 BIT 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 :-%

   Reads are equally tricky due to a nasty characteristic of the NCR5380.
   If the chip is in DMA mode for an READ, 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 command" reads, 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-reads, we must work around the
   problem.  The chosen fix is to DMA N-2 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 (p & SR_IO) {
1656 1657 1658 1659 1660 1661 1662
		if (!(hostdata->flags & FLAG_NO_DMA_FIXUPS)) {
			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_REGISTER);
				overrun = 1;
			}
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		}
	} else {
		int limit = 100;
		while (((tmp = NCR5380_read(BUS_AND_STATUS_REG)) & BASR_ACK) || (NCR5380_read(STATUS_REG) & SR_REQ)) {
			if (!(tmp & BASR_PHASE_MATCH))
				break;
			if (--limit < 0)
				break;
		}
	}

1674
	dprintk(NDEBUG_DMA, "scsi%d : polled DMA transfer complete, basr 0x%X, sr 0x%X\n", instance->host_no, tmp, NCR5380_read(STATUS_REG));
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	NCR5380_write(MODE_REG, MR_BASE);
	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);

	residue = NCR5380_dma_residual(instance);
	c -= residue;
	*count -= c;
	*data += c;
	*phase = NCR5380_read(STATUS_REG) & PHASE_MASK;

1685 1686
	if (!(hostdata->flags & FLAG_NO_DMA_FIXUPS) &&
	    *phase == p && (p & SR_IO) && residue == 0) {
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		if (overrun) {
1688
			dprintk(NDEBUG_DMA, "Got an input overrun, using saved byte\n");
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			**data = saved_data;
			*data += 1;
			*count -= 1;
			cnt = toPIO = 1;
		} else {
			printk("No overrun??\n");
			cnt = toPIO = 2;
		}
1697
		dprintk(NDEBUG_DMA, "Doing %d-byte PIO to 0x%X\n", cnt, *data);
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		NCR5380_transfer_pio(instance, phase, &cnt, data);
		*count -= toPIO - cnt;
	}

1702
	dprintk(NDEBUG_DMA, "Return with data ptr = 0x%X, count %d, last 0x%X, next 0x%X\n", *data, *count, *(*data + *count - 1), *(*data + *count));
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	return 0;

#elif defined(REAL_DMA)
	return 0;
#else				/* defined(REAL_DMA_POLL) */
	if (p & SR_IO) {
1709 1710 1711
		foo = NCR5380_pread(instance, d,
			hostdata->flags & FLAG_NO_DMA_FIXUP ? c : c - 1);
		if (!foo && !(hostdata->flags & FLAG_NO_DMA_FIXUP)) {
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			/*
			 * We can't disable DMA mode after successfully transferring 
			 * what we plan to be the last byte, since that would open up
			 * a race condition where if the target asserted REQ before 
			 * we got the DMA mode reset, the NCR5380 would have latched
			 * an additional byte into the INPUT DATA register and we'd
			 * have dropped it.
			 * 
			 * The workaround was to transfer one 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.
			 */

1734 1735 1736 1737 1738 1739 1740 1741 1742
			if (NCR5380_poll_politely(instance, BUS_AND_STATUS_REG,
			                          BASR_DRQ, BASR_DRQ, HZ) < 0) {
				foo = -1;
				shost_printk(KERN_ERR, instance, "PDMA read: DRQ timeout\n");
			}
			if (NCR5380_poll_politely(instance, STATUS_REG,
			                          SR_REQ, 0, HZ) < 0) {
				foo = -1;
				shost_printk(KERN_ERR, instance, "PDMA read: !REQ timeout\n");
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			}
1744
			d[c - 1] = NCR5380_read(INPUT_DATA_REG);
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		}
	} else {
		foo = NCR5380_pwrite(instance, d, c);
1748
		if (!foo && !(hostdata->flags & FLAG_NO_DMA_FIXUP)) {
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			/*
			 * 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.  
			 */
1753 1754 1755 1756 1757
			if (NCR5380_poll_politely2(instance,
			     BUS_AND_STATUS_REG, BASR_DRQ, BASR_DRQ,
			     BUS_AND_STATUS_REG, BASR_PHASE_MATCH, 0, HZ) < 0) {
				foo = -1;
				shost_printk(KERN_ERR, instance, "PDMA write: DRQ and phase timeout\n");
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			}
		}
	}
	NCR5380_write(MODE_REG, MR_BASE);
	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
1763
	NCR5380_read(RESET_PARITY_INTERRUPT_REG);
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	*data = d + c;
	*count = 0;
	*phase = NCR5380_read(STATUS_REG) & PHASE_MASK;
	return foo;
#endif				/* def REAL_DMA */
}
#endif				/* defined(REAL_DMA) | defined(PSEUDO_DMA) */

/*
 * 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.
 *
 * Locks: io_request_lock held by caller in IRQ mode
 */

static void NCR5380_information_transfer(struct Scsi_Host *instance) {
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	struct NCR5380_hostdata *hostdata = shost_priv(instance);
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	unsigned char msgout = NOP;
	int sink = 0;
	int len;
#if defined(PSEUDO_DMA) || defined(REAL_DMA_POLL)
	int transfersize;
#endif
	unsigned char *data;
	unsigned char phase, tmp, extended_msg[10], old_phase = 0xff;
1801
	struct scsi_cmnd *cmd;
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1803
	while ((cmd = hostdata->connected)) {
1804 1805
		struct NCR5380_cmd *ncmd = scsi_cmd_priv(cmd);

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		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);
			}
			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)
				printk("scsi%d : NDEBUG_NO_DATAOUT set, attempted DATAOUT aborted\n", instance->host_no);
				sink = 1;
				do_abort(instance);
				cmd->result = DID_ERROR << 16;
1830
				complete_cmd(instance, cmd);
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				return;
#endif
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			case PHASE_DATAIN:
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				/* 
				 * If there is no room left in the current buffer in the
				 * scatter-gather list, move onto the next one.
				 */

				if (!cmd->SCp.this_residual && cmd->SCp.buffers_residual) {
					++cmd->SCp.buffer;
					--cmd->SCp.buffers_residual;
					cmd->SCp.this_residual = cmd->SCp.buffer->length;
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					cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
1844
					dprintk(NDEBUG_INFORMATION, "scsi%d : %d bytes and %d buffers left\n", instance->host_no, cmd->SCp.this_residual, cmd->SCp.buffers_residual);
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				}
				/*
				 * 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.
				 */

#if defined(PSEUDO_DMA) || defined(REAL_DMA_POLL)
1857 1858 1859 1860 1861 1862
				transfersize = 0;
				if (!cmd->device->borken &&
				    !(hostdata->flags & FLAG_NO_PSEUDO_DMA))
					transfersize = NCR5380_dma_xfer_len(instance, cmd, phase);

				if (transfersize) {
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					len = transfersize;
					if (NCR5380_transfer_dma(instance, &phase, &len, (unsigned char **) &cmd->SCp.ptr)) {
						/*
						 * If the watchdog timer fires, all future accesses to this
						 * device will use the polled-IO.
						 */
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						scmd_printk(KERN_INFO, cmd,
							    "switching to slow handshake\n");
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						cmd->device->borken = 1;
						sink = 1;
						do_abort(instance);
						cmd->result = DID_ERROR << 16;
1875
						complete_cmd(instance, cmd);
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						/* XXX - need to source or sink data here, as appropriate */
					} else
						cmd->SCp.this_residual -= transfersize - len;
				} else
#endif				/* defined(PSEUDO_DMA) || defined(REAL_DMA_POLL) */
1881 1882
				{
					spin_unlock_irq(&hostdata->lock);
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					NCR5380_transfer_pio(instance, &phase, (int *) &cmd->SCp.this_residual, (unsigned char **)
							     &cmd->SCp.ptr);
1885 1886
					spin_lock_irq(&hostdata->lock);
				}
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				break;
			case PHASE_MSGIN:
				len = 1;
				data = &tmp;
				NCR5380_transfer_pio(instance, &phase, &len, &data);
				cmd->SCp.Message = tmp;

				switch (tmp) {
				case ABORT:
				case COMMAND_COMPLETE:
					/* Accept message by clearing ACK */
					sink = 1;
					NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
1900 1901 1902 1903
					dsprintk(NDEBUG_QUEUES, instance,
					         "COMMAND COMPLETE %p target %d lun %llu\n",
					         cmd, scmd_id(cmd), cmd->device->lun);

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					hostdata->connected = NULL;

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					cmd->result &= ~0xffff;
					cmd->result |= cmd->SCp.Status;
					cmd->result |= cmd->SCp.Message << 8;
1909

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					if (cmd->cmnd[0] == REQUEST_SENSE)
1911
						complete_cmd(instance, cmd);
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					else {
						if (cmd->SCp.Status == SAM_STAT_CHECK_CONDITION ||
						    cmd->SCp.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);
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					}

					/* 
					 * Restore phase bits to 0 so an interrupted selection, 
					 * arbitration can resume.
					 */
					NCR5380_write(TARGET_COMMAND_REG, 0);
1928 1929 1930

					/* Enable reselect interrupts */
					NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
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					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;
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						hostdata->busy[cmd->device->id] |= (1 << (cmd->device->lun & 0xFF));
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						break;
					default:
						break;
					}
1945
					break;
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				case DISCONNECT:{
						/* Accept message by clearing ACK */
						NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
						hostdata->connected = NULL;
1950
						list_add(&ncmd->list, &hostdata->disconnected);
1951 1952 1953 1954
						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);

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						/* 
						 * Restore phase bits to 0 so an interrupted selection, 
						 * arbitration can resume.
						 */
						NCR5380_write(TARGET_COMMAND_REG, 0);

						/* Enable reselect interrupts */
						NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
						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:
/* 
 * Extended messages are sent in the following format :
 * Byte         
 * 0            EXTENDED_MESSAGE == 1
 * 1            length (includes one byte for code, doesn't 
 *              include first two bytes)
 * 2            code
 * 3..length+1  arguments
 *
 * Start the extended message buffer with the EXTENDED_MESSAGE
1991
 * byte, since spi_print_msg() wants the whole thing.  
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 */
					extended_msg[0] = EXTENDED_MESSAGE;
					/* Accept first byte by clearing ACK */
					NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
1996 1997 1998

					spin_unlock_irq(&hostdata->lock);

1999
					dprintk(NDEBUG_EXTENDED, "scsi%d : receiving extended message\n", instance->host_no);
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					len = 2;
					data = extended_msg + 1;
					phase = PHASE_MSGIN;
					NCR5380_transfer_pio(instance, &phase, &len, &data);

2006
					dprintk(NDEBUG_EXTENDED, "scsi%d : length=%d, code=0x%02x\n", instance->host_no, (int) extended_msg[1], (int) extended_msg[2]);
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2008 2009
					if (!len && extended_msg[1] > 0 &&
					    extended_msg[1] <= sizeof(extended_msg) - 2) {
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						/* 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);
2017
						dprintk(NDEBUG_EXTENDED, "scsi%d : message received, residual %d\n", instance->host_no, len);
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						switch (extended_msg[2]) {
						case EXTENDED_SDTR:
						case EXTENDED_WDTR:
						case EXTENDED_MODIFY_DATA_POINTER:
						case EXTENDED_EXTENDED_IDENTIFY:
							tmp = 0;
						}
					} else if (len) {
						printk("scsi%d: error receiving extended message\n", instance->host_no);
						tmp = 0;
					} else {
						printk("scsi%d: extended message code %02x length %d is too long\n", instance->host_no, extended_msg[2], extended_msg[1]);
						tmp = 0;
					}
2033 2034 2035 2036 2037

					spin_lock_irq(&hostdata->lock);
					if (!hostdata->connected)
						return;

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					/* Fall through to reject message */

					/* 
					 * If we get something weird that we aren't expecting, 
					 * reject it.
					 */
				default:
					if (!tmp) {
						printk("scsi%d: rejecting message ", instance->host_no);
2047
						spi_print_msg(extended_msg);
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						printk("\n");
					} else if (tmp != EXTENDED_MESSAGE)
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						scmd_printk(KERN_INFO, cmd,
							"rejecting unknown message %02x\n",tmp);
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					else
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						scmd_printk(KERN_INFO, cmd,
							"rejecting unknown extended message code %02x, length %d\n", extended_msg[1], extended_msg[0]);
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					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);
				if (msgout == ABORT) {
					hostdata->connected = NULL;
					cmd->result = DID_ERROR << 16;
2069
					complete_cmd(instance, cmd);
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					NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
					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);
				break;
			case PHASE_STATIN:
				len = 1;
				data = &tmp;
				NCR5380_transfer_pio(instance, &phase, &len, &data);
				cmd->SCp.Status = tmp;
				break;
			default:
				printk("scsi%d : unknown phase\n", instance->host_no);
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				NCR5380_dprint(NDEBUG_ANY, instance);
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			}	/* switch(phase) */
2095
		} else {
2096
			spin_unlock_irq(&hostdata->lock);
2097
			NCR5380_poll_politely(instance, STATUS_REG, SR_REQ, SR_REQ, HZ);
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			spin_lock_irq(&hostdata->lock);
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		}
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	}
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}

/*
 * Function : void NCR5380_reselect (struct Scsi_Host *instance)
 *
 * Purpose : does reselection, initializing the instance->connected 
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 *      field to point to the scsi_cmnd for which the I_T_L or I_T_L_Q
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 *      nexus has been reestablished,
 *      
 * Inputs : instance - this instance of the NCR5380.
 *
 * Locks: io_request_lock held by caller if IRQ driven
 */

static void NCR5380_reselect(struct Scsi_Host *instance) {
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	struct NCR5380_hostdata *hostdata = shost_priv(instance);
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	unsigned char target_mask;
	unsigned char lun, phase;
	int len;
	unsigned char msg[3];
	unsigned char *data;
2122 2123
	struct NCR5380_cmd *ncmd;
	struct scsi_cmnd *tmp;
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	/*
	 * 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);
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	dprintk(NDEBUG_RESELECTION, "scsi%d : reselect\n", instance->host_no);
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	/* 
	 * 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);
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	if (NCR5380_poll_politely(instance,
	                          STATUS_REG, SR_SEL, 0, 2 * HZ) < 0) {
		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
		return;
	}
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	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);

	/*
	 * Wait for target to go into MSGIN.
	 */

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	if (NCR5380_poll_politely(instance,
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	                          STATUS_REG, SR_REQ, SR_REQ, 2 * HZ) < 0) {
		do_abort(instance);
		return;
	}
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	len = 1;
	data = msg;
	phase = PHASE_MSGIN;
	NCR5380_transfer_pio(instance, &phase, &len, &data);

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	if (len) {
		do_abort(instance);
		return;
	}

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	if (!(msg[0] & 0x80)) {
2173
		shost_printk(KERN_ERR, instance, "expecting IDENTIFY message, got ");
2174
		spi_print_msg(msg);
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		printk("\n");
		do_abort(instance);
		return;
	}
	lun = msg[0] & 0x07;
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	/*
	 * 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.
	 */
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	/*
	 * 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.
	 */
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2192 2193 2194 2195 2196 2197 2198 2199
	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;
2200
			break;
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		}
	}
2203 2204 2205 2206 2207

	if (tmp) {
		dsprintk(NDEBUG_RESELECTION | NDEBUG_QUEUES, instance,
		         "reselect: removed %p from disconnected queue\n", tmp);
	} else {
2208 2209 2210 2211 2212 2213
		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.
		 */
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		do_abort(instance);
2215
		return;
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	}
2217 2218 2219 2220 2221 2222 2223

	/* Accept message by clearing ACK */
	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);

	hostdata->connected = tmp;
	dprintk(NDEBUG_RESELECTION, "scsi%d : nexus established, target = %d, lun = %llu, tag = %d\n",
	        instance->host_no, tmp->device->id, tmp->device->lun, tmp->tag);
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}

/*
 * Function : void NCR5380_dma_complete (struct Scsi_Host *instance)
 *
 * Purpose : called by interrupt handler when DMA finishes or a phase
 *      mismatch occurs (which would finish the DMA transfer).  
 *
 * Inputs : instance - this instance of the NCR5380.
 *
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 * Returns : pointer to the scsi_cmnd structure for which the I_T_L
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 *      nexus has been reestablished, on failure NULL is returned.
 */

#ifdef REAL_DMA
static void NCR5380_dma_complete(NCR5380_instance * instance) {
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	struct NCR5380_hostdata *hostdata = shost_priv(instance);
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	int transferred;

	/*
	 * XXX this might not be right.
	 *
	 * Wait for final byte to transfer, ie wait for ACK to go false.
	 *
	 * We should use the Last Byte Sent bit, unfortunately this is 
	 * not available on the 5380/5381 (only the various CMOS chips)
	 *
	 * FIXME: timeout, and need to handle long timeout/irq case
	 */

	NCR5380_poll_politely(instance, BUS_AND_STATUS_REG, BASR_ACK, 0, 5*HZ);

	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);

	/*
	 * The only places we should see a phase mismatch and have to send
	 * data from the same set of pointers will be the data transfer
	 * phases.  So, residual, requested length are only important here.
	 */

	if (!(hostdata->connected->SCp.phase & SR_CD)) {
		transferred = instance->dmalen - NCR5380_dma_residual();
		hostdata->connected->SCp.this_residual -= transferred;
		hostdata->connected->SCp.ptr += transferred;
	}
}
#endif				/* def REAL_DMA */

/*
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 * Function : int NCR5380_abort (struct scsi_cmnd *cmd)
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 *
 * Purpose : abort a command
 *
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 * Inputs : cmd - the scsi_cmnd to abort, code - code to set the
2278
 *      host byte of the result field to, if zero DID_ABORTED is
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 *      used.
 *
2281
 * Returns : SUCCESS - success, FAILED on failure.
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 *
2283 2284
 *	XXX - there is no way to abort the command that is currently
 *	connected, you have to wait for it to complete.  If this is
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 *	a problem, we could implement longjmp() / setjmp(), setjmp()
 *	called where the loop started in NCR5380_main().
 *
 * Locks: host lock taken by caller
 */

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static int NCR5380_abort(struct scsi_cmnd *cmd)
{
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	struct Scsi_Host *instance = cmd->device->host;
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	struct NCR5380_hostdata *hostdata = shost_priv(instance);
2295
	unsigned long flags;
2296

2297 2298
	spin_lock_irqsave(&hostdata->lock, flags);

2299 2300 2301
#if (NDEBUG & NDEBUG_ANY)
	scmd_printk(KERN_INFO, cmd, "aborting command\n");
#endif
2302 2303
	NCR5380_dprint(NDEBUG_ANY, instance);
	NCR5380_dprint_phase(NDEBUG_ANY, instance);
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2305
	spin_unlock_irqrestore(&hostdata->lock, flags);
2306

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	return FAILED;
}


2311 2312 2313
/**
 * NCR5380_bus_reset - reset the SCSI bus
 * @cmd: SCSI command undergoing EH
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 *
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 * Returns SUCCESS
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 */

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static int NCR5380_bus_reset(struct scsi_cmnd *cmd)
2319 2320
{
	struct Scsi_Host *instance = cmd->device->host;
2321 2322
	struct NCR5380_hostdata *hostdata = shost_priv(instance);
	unsigned long flags;
2323

2324
	spin_lock_irqsave(&hostdata->lock, flags);
2325 2326 2327 2328

#if (NDEBUG & NDEBUG_ANY)
	scmd_printk(KERN_INFO, cmd, "performing bus reset\n");
#endif
2329 2330
	NCR5380_dprint(NDEBUG_ANY, instance);
	NCR5380_dprint_phase(NDEBUG_ANY, instance);
2331 2332

	do_reset(instance);
2333

2334
	spin_unlock_irqrestore(&hostdata->lock, flags);
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	return SUCCESS;
}