arch/arm/mach-ixp2000/ixdp2400.c


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182

/*
 * arch/arm/mach-ixp2000/ixdp2400.c
 *
 * IXDP2400 platform support
 *
 * Original Author: Naeem Afzal <naeem.m.afzal@intel.com>
 * Maintainer: Deepak Saxena <dsaxena@plexity.net>
 *
 * Copyright (C) 2002 Intel Corp.
 * Copyright (C) 2003-2004 MontaVista Software, Inc.
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 */
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/bitops.h>
#include <linux/pci.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/io.h>

#include <asm/irq.h>
#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/system.h>
#include <mach/hardware.h>
#include <asm/mach-types.h>

#include <asm/mach/pci.h>
#include <asm/mach/map.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>
#include <asm/mach/flash.h>
#include <asm/mach/arch.h>

/*************************************************************************
 * IXDP2400 timer tick
 *************************************************************************/
static void __init ixdp2400_timer_init(void)
{
	int numerator, denominator;
	int denom_array[] = {2, 4, 8, 16, 1, 2, 4, 8};

	numerator = (*(IXDP2400_CPLD_SYS_CLK_M) & 0xFF) *2;
	denominator = denom_array[(*(IXDP2400_CPLD_SYS_CLK_N) & 0x7)];

	ixp2000_init_time(((3125000 * numerator) / (denominator)) / 2);
}

static struct sys_timer ixdp2400_timer = {
	.init		= ixdp2400_timer_init,
	.offset		= ixp2000_gettimeoffset,
};

/*************************************************************************
 * IXDP2400 PCI
 *************************************************************************/
void __init ixdp2400_pci_preinit(void)
{
	ixp2000_reg_write(IXP2000_PCI_ADDR_EXT, 0x00100000);
	ixp2000_pci_preinit();
	pcibios_setup("firmware");
}

int ixdp2400_pci_setup(int nr, struct pci_sys_data *sys)
{
	sys->mem_offset = 0xe0000000;

	ixp2000_pci_setup(nr, sys);

	return 1;
}

static int __init ixdp2400_pci_map_irq(struct pci_dev *dev, u8 slot, u8 pin)
{
	if (ixdp2x00_master_npu()) {

		/*
		 * Root bus devices.  Slave NPU is only one with interrupt.
		 * Everything else, we just return -1 b/c nothing else
		 * on the root bus has interrupts.
		 */
		if(!dev->bus->self) {
			if(dev->devfn == IXDP2X00_SLAVE_NPU_DEVFN )
				return IRQ_IXDP2400_INGRESS_NPU;

			return -1;
		}

		/*
		 * Bridge behind the PMC slot.
		 * NOTE: Only INTA from the PMC slot is routed. VERY BAD.
		 */
		if(dev->bus->self->devfn == IXDP2X00_PMC_DEVFN &&
			dev->bus->parent->self->devfn == IXDP2X00_P2P_DEVFN &&
			!dev->bus->parent->self->bus->parent)
				  return IRQ_IXDP2400_PMC;

		/*
		 * Device behind the first bridge
		 */
		if(dev->bus->self->devfn == IXDP2X00_P2P_DEVFN) {
			switch(dev->devfn) {
				case IXDP2400_MASTER_ENET_DEVFN:	
					return IRQ_IXDP2400_ENET;	
			
				case IXDP2400_MEDIA_DEVFN:
					return IRQ_IXDP2400_MEDIA_PCI;

				case IXDP2400_SWITCH_FABRIC_DEVFN:
					return IRQ_IXDP2400_SF_PCI;

				case IXDP2X00_PMC_DEVFN:
					return IRQ_IXDP2400_PMC;
			}
		}

		return -1;
	} else return IRQ_IXP2000_PCIB; /* Slave NIC interrupt */
}


static void ixdp2400_pci_postinit(void)
{
	struct pci_dev *dev;

	if (ixdp2x00_master_npu()) {
		dev = pci_get_bus_and_slot(1, IXDP2400_SLAVE_ENET_DEVFN);
		pci_remove_bus_device(dev);
		pci_dev_put(dev);
	} else {
		dev = pci_get_bus_and_slot(1, IXDP2400_MASTER_ENET_DEVFN);
		pci_remove_bus_device(dev);
		pci_dev_put(dev);

		ixdp2x00_slave_pci_postinit();
	}
}

static struct hw_pci ixdp2400_pci __initdata = {
	.nr_controllers	= 1,
	.setup		= ixdp2400_pci_setup,
	.preinit	= ixdp2400_pci_preinit,
	.postinit	= ixdp2400_pci_postinit,
	.scan		= ixp2000_pci_scan_bus,
	.map_irq	= ixdp2400_pci_map_irq,
};

int __init ixdp2400_pci_init(void)
{
	if (machine_is_ixdp2400())
		pci_common_init(&ixdp2400_pci);

	return 0;
}

subsys_initcall(ixdp2400_pci_init);

void __init ixdp2400_init_irq(void)
{
	ixdp2x00_init_irq(IXDP2400_CPLD_INT_STAT, IXDP2400_CPLD_INT_MASK, IXDP2400_NR_IRQS);
}

MACHINE_START(IXDP2400, "Intel IXDP2400 Development Platform")
	/* Maintainer: MontaVista Software, Inc. */
	.phys_io	= IXP2000_UART_PHYS_BASE,
	.io_pg_offst	= ((IXP2000_UART_VIRT_BASE) >> 18) & 0xfffc,
	.boot_params	= 0x00000100,
	.map_io		= ixdp2x00_map_io,
	.init_irq	= ixdp2400_init_irq,
	.timer		= &ixdp2400_timer,
	.init_machine	= ixdp2x00_init_machine,
MACHINE_END
/*
 * 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
 *
 * DISTRIBUTION RELEASE 6.
 *
 * 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
 */

/*
 * ++roman: To port the 5380 driver to the Atari, I had to do some changes in
 * this file, too:
 *
 *  - Some of the debug statements were incorrect (undefined variables and the
 *    like). I fixed that.
 *
 *  - In information_transfer(), I think a #ifdef was wrong. Looking at the
 *    possible DMA transfer size should also happen for REAL_DMA. I added this
 *    in the #if statement.
 *
 *  - When using real DMA, information_transfer() should return in a DATAOUT
 *    phase after starting the DMA. It has nothing more to do.
 *
 *  - The interrupt service routine should run main after end of DMA, too (not
 *    only after RESELECTION interrupts). Additionally, it should _not_ test
 *    for more interrupts after running main, since a DMA process may have
 *    been started and interrupts are turned on now. The new int could happen
 *    inside the execution of NCR5380_intr(), leading to recursive
 *    calls.
 *
 *  - I've added a function merge_contiguous_buffers() that tries to
 *    merge scatter-gather buffers that are located at contiguous
 *    physical addresses and can be processed with the same DMA setup.
 *    Since most scatter-gather operations work on a page (4K) of
 *    4 buffers (1K), in more than 90% of all cases three interrupts and
 *    DMA setup actions are saved.
 *
 * - I've deleted all the stuff for AUTOPROBE_IRQ, REAL_DMA_POLL, PSEUDO_DMA
 *    and USLEEP, because these were messing up readability and will never be
 *    needed for Atari SCSI.
 *
 * - I've revised the NCR5380_main() calling scheme (relax the 'main_running'
 *   stuff), and 'main' is executed in a bottom half if awoken by an
 *   interrupt.
 *
 * - The code was quite cluttered up by "#if (NDEBUG & NDEBUG_*) printk..."
 *   constructs. In my eyes, this made the source rather unreadable, so I
 *   finally replaced that by the *_PRINTK() macros.
 *
 */

/*
 * Further development / testing that should be done :
 * 1.  Test linked command handling code after Eric is ready with
 *     the high level code.
 */
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_transport_spi.h>

#if (NDEBUG & NDEBUG_LISTS)
#define LIST(x, y)						\
	do {							\
		printk("LINE:%d   Adding %p to %p\n",		\
		       __LINE__, (void*)(x), (void*)(y));	\
		if ((x) == (y))					\
			udelay(5);				\
	} while (0)
#define REMOVE(w, x, y, z)					\
	do {							\
		printk("LINE:%d   Removing: %p->%p  %p->%p \n",	\
		       __LINE__, (void*)(w), (void*)(x),	\
		       (void*)(y), (void*)(z));			\
		if ((x) == (y))					\
			udelay(5);				\
	} while (0)
#else
#define LIST(x,y)
#define REMOVE(w,x,y,z)
#endif

#ifndef notyet
#undef LINKED
#endif

/*
 * Design
 * Issues :
 *
 * The other Linux SCSI drivers were written when Linux was Intel PC-only,
 * and specifically for each board rather than each chip.  This makes their
 * adaptation to platforms like the Mac (Some of which use NCR5380's)
 * more difficult than it has to be.
 *
 * Also, many of the SCSI drivers were written before the command queuing
 * routines were implemented, meaning their implementations of queued
 * commands were hacked on rather than designed in from the start.
 *
 * When I designed the Linux SCSI drivers I figured that
 * while having two different SCSI boards in a system might be useful
 * for debugging things, two of the same type wouldn't be used.
 * Well, I was wrong and a number of users have mailed me about running
 * multiple high-performance SCSI boards in a server.
 *
 * Finally, when I get questions from users, I have no idea what
 * revision of my driver they are running.
 *
 * This driver attempts to address these problems :
 * This is a generic 5380 driver.  To use it on a different platform,
 * one simply writes appropriate system specific macros (ie, data
 * transfer - some PC's will use the I/O bus, 68K's must use
 * memory mapped) and drops this file in their 'C' wrapper.
 *
 * As far as command queueing, two queues are maintained for
 * each 5380 in the system - commands that haven't been issued yet,
 * and commands that are currently executing.  This means that an
 * unlimited number of commands may be queued, letting
 * more commands propagate from the higher driver levels giving higher
 * throughput.  Note that both I_T_L and I_T_L_Q nexuses are supported,
 * allowing multiple commands to propagate all the way to a SCSI-II device
 * while a command is already executing.
 *
 * To solve the multiple-boards-in-the-same-system problem,
 * there is a separate instance structure for each instance
 * of a 5380 in the system.  So, multiple NCR5380 drivers will
 * be able to coexist with appropriate changes to the high level
 * SCSI code.
 *
 * A NCR5380_PUBLIC_REVISION macro is provided, with the release
 * number (updated for each public release) printed by the
 * NCR5380_print_options command, which should be called from the
 * wrapper detect function, so that I know what release of the driver
 * users are using.
 *
 * Issues specific to the NCR5380 :
 *
 * When used in a PIO or pseudo-dma mode, the NCR5380 is a braindead
 * piece of hardware that requires you to sit in a loop polling for
 * the REQ signal as long as you are connected.  Some devices are
 * brain dead (ie, many TEXEL CD ROM drives) and won't disconnect
 * while doing long seek operations.
 *
 * The workaround for this is to keep track of devices that have
 * disconnected.  If the device hasn't disconnected, for commands that
 * should disconnect, we do something like
 *
 * while (!REQ is asserted) { sleep for N usecs; poll for M usecs }
 *
 * Some tweaking of N and M needs to be done.  An algorithm based
 * on "time to data" would give the best results as long as short time
 * to datas (ie, on the same track) were considered, however these
 * broken devices are the exception rather than the rule and I'd rather
 * spend my time optimizing for the normal case.
 *
 * Architecture :
 *
 * At the heart of the design is a coroutine, NCR5380_main,
 * which is started when not running by the interrupt handler,
 * timer, and queue command function.  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 USLEEP
 * was defined, and 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 :
 * AUTOSENSE - if defined, REQUEST SENSE will be performed automatically
 *	for commands that return with a CHECK CONDITION status.
 *
 * LINKED - if defined, linked commands are supported.
 *
 * REAL_DMA - if defined, REAL DMA is used during the data transfer phases.
 *
 * SUPPORT_TAGS - if defined, SCSI-2 tagged queuing is used where possible
 *
 * These macros MUST be defined :
 *
 * NCR5380_read(register)  - read from the specified register
 *
 * NCR5380_write(register, value) - write to the specific register
 *
 * 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);
 *
 * If nothing specific to this implementation needs doing (ie, with external
 * hardware), you must also define
 *
 * NCR5380_queue_command
 * NCR5380_reset
 * NCR5380_abort
 * NCR5380_proc_info
 *
 * to be the global entry points into the specific driver, ie
 * #define NCR5380_queue_command t128_queue_command.
 *
 * If this is not done, the routines will be defined as static functions
 * with the NCR5380* names and the user must provide a globally
 * accessible wrapper function.
 *
 * 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.  Before the specific driver initialization
 * code finishes, NCR5380_print_options should be called.
 */

static struct Scsi_Host *first_instance = NULL;
static struct scsi_host_template *the_template = NULL;

/* Macros ease life... :-) */
#define	SETUP_HOSTDATA(in)				\
    struct NCR5380_hostdata *hostdata =			\
	(struct NCR5380_hostdata *)(in)->hostdata
#define	HOSTDATA(in) ((struct NCR5380_hostdata *)(in)->hostdata)

#define	NEXT(cmd)		((Scsi_Cmnd *)(cmd)->host_scribble)
#define	SET_NEXT(cmd,next)	((cmd)->host_scribble = (void *)(next))
#define	NEXTADDR(cmd)		((Scsi_Cmnd **)&(cmd)->host_scribble)

#define	HOSTNO		instance->host_no
#define	H_NO(cmd)	(cmd)->device->host->host_no

#ifdef SUPPORT_TAGS

/*
 * Functions for handling tagged queuing
 * =====================================
 *
 * ++roman (01/96): Now I've implemented SCSI-2 tagged queuing. Some notes:
 *
 * Using consecutive numbers for the tags is no good idea in my eyes. There
 * could be wrong re-usings if the counter (8 bit!) wraps and some early
 * command has been preempted for a long time. My solution: a bitfield for
 * remembering used tags.
 *
 * There's also the problem that each target has a certain queue size, but we
 * cannot know it in advance :-( We just see a QUEUE_FULL status being
 * returned. So, in this case, the driver internal queue size assumption is
 * reduced to the number of active tags if QUEUE_FULL is returned by the
 * target. The command is returned to the mid-level, but with status changed
 * to BUSY, since --as I've seen-- the mid-level can't handle QUEUE_FULL
 * correctly.
 *
 * We're also not allowed running tagged commands as long as an untagged
 * command is active. And REQUEST SENSE commands after a contingent allegiance
 * condition _must_ be untagged. To keep track whether an untagged command has
 * been issued, the host->busy array is still employed, as it is without
 * support for tagged queuing.
 *
 * One could suspect that there are possible race conditions between
 * is_lun_busy(), cmd_get_tag() and cmd_free_tag(). But I think this isn't the
 * case: is_lun_busy() and cmd_get_tag() are both called from NCR5380_main(),
 * which already guaranteed to be running at most once. It is also the only
 * place where tags/LUNs are allocated. So no other allocation can slip
 * between that pair, there could only happen a reselection, which can free a
 * tag, but that doesn't hurt. Only the sequence in cmd_free_tag() becomes
 * important: the tag bit must be cleared before 'nr_allocated' is decreased.
 */

/* -1 for TAG_NONE is not possible with unsigned char cmd->tag */
#undef TAG_NONE
#define TAG_NONE 0xff

typedef struct {
	DECLARE_BITMAP(allocated, MAX_TAGS);
	int nr_allocated;
	int queue_size;
} TAG_ALLOC;

static TAG_ALLOC TagAlloc[8][8];	/* 8 targets and 8 LUNs */


static void __init init_tags(void)
{
	int target, lun;
	TAG_ALLOC *ta;

	if (!setup_use_tagged_queuing)
		return;

	for (target = 0; target < 8; ++target) {
		for (lun = 0; lun < 8; ++lun) {
			ta = &TagAlloc[target][lun];
			bitmap_zero(ta->allocated, MAX_TAGS);
			ta->nr_allocated = 0;
			/* At the beginning, assume the maximum queue size we could
			 * support (MAX_TAGS). This value will be decreased if the target
			 * returns QUEUE_FULL status.
			 */
			ta->queue_size = MAX_TAGS;
		}
	}
}


/* Check if we can issue a command to this LUN: First see if the LUN is marked
 * busy by an untagged command. If the command should use tagged queuing, also
 * check that there is a free tag and the target's queue won't overflow. This
 * function should be called with interrupts disabled to avoid race
 * conditions.
 */

static int is_lun_busy(Scsi_Cmnd *cmd, int should_be_tagged)
{
	SETUP_HOSTDATA(cmd->device->host);

	if (hostdata->busy[cmd->device->id] & (1 << cmd->device->lun))
		return 1;
	if (!should_be_tagged ||
	    !setup_use_tagged_queuing || !cmd->device->tagged_supported)
		return 0;
	if (TagAlloc[cmd->device->id][cmd->device->lun].nr_allocated >=
	    TagAlloc[cmd->device->id][cmd->device->lun].queue_size) {
		TAG_PRINTK("scsi%d: target %d lun %d: no free tags\n",
			   H_NO(cmd), cmd->device->id, cmd->device->lun);
		return 1;
	}
	return 0;
}


/* Allocate a tag for a command (there are no checks anymore, check_lun_busy()
 * must be called before!), or reserve the LUN in 'busy' if the command is
 * untagged.
 */

static void cmd_get_tag(Scsi_Cmnd *cmd, int should_be_tagged)
{
	SETUP_HOSTDATA(cmd->device->host);

	/* If we or the target don't support tagged queuing, allocate the LUN for
	 * an untagged command.
	 */
	if (!should_be_tagged ||
	    !setup_use_tagged_queuing || !cmd->device->tagged_supported) {
		cmd->tag = TAG_NONE;
		hostdata->busy[cmd->device->id] |= (1 << cmd->device->lun);
		TAG_PRINTK("scsi%d: target %d lun %d now allocated by untagged "
			   "command\n", H_NO(cmd), cmd->device->id, cmd->device->lun);
	} else {
		TAG_ALLOC *ta = &TagAlloc[cmd->device->id][cmd->device->lun];

		cmd->tag = find_first_zero_bit(ta->allocated, MAX_TAGS);
		set_bit(cmd->tag, ta->allocated);
		ta->nr_allocated++;
		TAG_PRINTK("scsi%d: using tag %d for target %d lun %d "
			   "(now %d tags in use)\n",
			   H_NO(cmd), cmd->tag, cmd->device->id,
			   cmd->device->lun, ta->nr_allocated);
	}
}


/* Mark the tag of command 'cmd' as free, or in case of an untagged command,
 * unlock the LUN.
 */

static void cmd_free_tag(Scsi_Cmnd *cmd)
{
	SETUP_HOSTDATA(cmd->device->host);

	if (cmd->tag == TAG_NONE) {
		hostdata->busy[cmd->device->id] &= ~(1 << cmd->device->lun);
		TAG_PRINTK("scsi%d: target %d lun %d untagged cmd finished\n",
			   H_NO(cmd), cmd->device->id, cmd->device->lun);
	} else if (cmd->tag >= MAX_TAGS) {
		printk(KERN_NOTICE "scsi%d: trying to free bad tag %d!\n",
		       H_NO(cmd), cmd->tag);
	} else {
		TAG_ALLOC *ta = &TagAlloc[cmd->device->id][cmd->device->lun];
		clear_bit(cmd->tag, ta->allocated);
		ta->nr_allocated--;
		TAG_PRINTK("scsi%d: freed tag %d for target %d lun %d\n",
			   H_NO(cmd), cmd->tag, cmd->device->id, cmd->device->lun);
	}
}


static void free_all_tags(void)
{
	int target, lun;
	TAG_ALLOC *ta;

	if (!setup_use_tagged_queuing)
		return;

	for (target = 0; target < 8; ++target) {
		for (lun = 0; lun < 8; ++lun) {
			ta = &TagAlloc[target][lun];
			bitmap_zero(ta->allocated, MAX_TAGS);
			ta->nr_allocated = 0;
		}
	}
}

#endif /* SUPPORT_TAGS */


/*
 * Function: void merge_contiguous_buffers( Scsi_Cmnd *cmd )
 *
 * Purpose: Try to merge several scatter-gather requests into one DMA
 *    transfer. This is possible if the scatter buffers lie on
 *    physical contiguous addresses.
 *
 * Parameters: Scsi_Cmnd *cmd
 *    The command to work on. The first scatter buffer's data are
 *    assumed to be already transfered into ptr/this_residual.
 */

static void merge_contiguous_buffers(Scsi_Cmnd *cmd)
{
	unsigned long endaddr;
#if (NDEBUG & NDEBUG_MERGING)
	unsigned long oldlen = cmd->SCp.this_residual;
	int cnt = 1;
#endif

	for (endaddr = virt_to_phys(cmd->SCp.ptr + cmd->SCp.this_residual - 1) + 1;
	     cmd->SCp.buffers_residual &&
	     virt_to_phys(sg_virt(&cmd->SCp.buffer[1])) == endaddr;) {
		MER_PRINTK("VTOP(%p) == %08lx -> merging\n",
			   page_address(sg_page(&cmd->SCp.buffer[1])), endaddr);
#if (NDEBUG & NDEBUG_MERGING)
		++cnt;
#endif
		++cmd->SCp.buffer;
		--cmd->SCp.buffers_residual;
		cmd->SCp.this_residual += cmd->SCp.buffer->length;
		endaddr += cmd->SCp.buffer->length;
	}
#if (NDEBUG & NDEBUG_MERGING)
	if (oldlen != cmd->SCp.this_residual)
		MER_PRINTK("merged %d buffers from %p, new length %08x\n",
			   cnt, cmd->SCp.ptr, cmd->SCp.this_residual);
#endif
}

/*
 * Function : void initialize_SCp(Scsi_Cmnd *cmd)
 *
 * Purpose : initialize the saved data pointers for cmd to point to the
 *	start of the buffer.
 *
 * Inputs : cmd - Scsi_Cmnd structure to have pointers reset.
 */

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

	if (scsi_bufflen(cmd)) {
		cmd->SCp.buffer = scsi_sglist(cmd);
		cmd->SCp.buffers_residual = scsi_sg_count(cmd) - 1;
		cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
		cmd->SCp.this_residual = cmd->SCp.buffer->length;
		/* ++roman: Try to merge some scatter-buffers if they are at
		 * contiguous physical addresses.
		 */
		merge_contiguous_buffers(cmd);
	} else {
		cmd->SCp.buffer = NULL;
		cmd->SCp.buffers_residual = 0;
		cmd->SCp.ptr = NULL;
		cmd->SCp.this_residual = 0;
	}
}

#include <linux/delay.h>

#if NDEBUG
static struct {
	unsigned char mask;
	const char *name;
} signals[] = {
	{ SR_DBP, "PARITY"}, { SR_RST, "RST" }, { SR_BSY, "BSY" },
	{ SR_REQ, "REQ" }, { SR_MSG, "MSG" }, { SR_CD,  "CD" }, { SR_IO, "IO" },
	{ SR_SEL, "SEL" }, {0, NULL}
}, basrs[] = {
	{BASR_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_ENABLE_EOP_INTR,"MODE EOP INTR"},
	{MR_MONITOR_BSY, "MODE MONITOR BSY"},
	{MR_DMA_MODE, "MODE DMA"}, {MR_ARBITRATE, "MODE ARBITRATION"},
	{0, NULL}
};

/*
 * Function : void NCR5380_print(struct Scsi_Host *instance)
 *
 * Purpose : print the SCSI bus signals for debugging purposes
 *
 * Input : instance - which NCR5380
 */

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

	local_irq_save(flags);
	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);
	local_irq_restore(flags);
	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");
}

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

/*
 * Function : void NCR5380_print_phase(struct Scsi_Host *instance)
 *
 * Purpose : print the current SCSI phase for debugging purposes
 *
 * Input : instance - which NCR5380
 */

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

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

#else /* !NDEBUG */

/* dummies... */
static inline void NCR5380_print(struct Scsi_Host *instance)
{
};
static inline void NCR5380_print_phase(struct Scsi_Host *instance)
{
};

#endif

/*
 * ++roman: New scheme of calling NCR5380_main()
 *
 * If we're not in an interrupt, we can call our main directly, it cannot be
 * already running. Else, we queue it on a task queue, if not 'main_running'
 * tells us that a lower level is already executing it. This way,
 * 'main_running' needs not be protected in a special way.
 *
 * queue_main() is a utility function for putting our main onto the task
 * queue, if main_running is false. It should be called only from a
 * interrupt or bottom half.
 */

#include <linux/gfp.h>
#include <linux/workqueue.h>
#include <linux/interrupt.h>

static volatile int main_running;
static DECLARE_WORK(NCR5380_tqueue, NCR5380_main);

static inline void queue_main(void)
{
	if (!main_running) {
		/* If in interrupt and NCR5380_main() not already running,
		   queue it on the 'immediate' task queue, to be processed
		   immediately after the current interrupt processing has
		   finished. */
		schedule_work(&NCR5380_tqueue);
	}
	/* else: nothing to do: the running NCR5380_main() will pick up
	   any newly queued command. */
}


static inline void NCR5380_all_init(void)
{
	static int done = 0;
	if (!done) {
		INI_PRINTK("scsi : NCR5380_all_init()\n");
		done = 1;
	}
}


/*
 * Function : void NCR58380_print_options (struct Scsi_Host *instance)
 *
 * Purpose : called by probe code indicating the NCR5380 driver
 *	     options that were selected.
 *
 * Inputs : instance, pointer to this instance.  Unused.
 */

static void __init NCR5380_print_options(struct Scsi_Host *instance)
{
	printk(" generic options"
#ifdef AUTOSENSE
	       " AUTOSENSE"
#endif
#ifdef REAL_DMA
	       " REAL DMA"
#endif
#ifdef PARITY
	       " PARITY"
#endif
#ifdef SUPPORT_TAGS
	       " SCSI-2 TAGGED QUEUING"
#endif
	       );
	printk(" generic release=%d", NCR5380_PUBLIC_RELEASE);
}

/*
 * Function : void NCR5380_print_status (struct Scsi_Host *instance)
 *
 * Purpose : print commands in the various queues, called from
 *	NCR5380_abort and NCR5380_debug to aid debugging.
 *
 * Inputs : instance, pointer to this instance.
 */

static void NCR5380_print_status(struct Scsi_Host *instance)
{
	char *pr_bfr;
	char *start;
	int len;

	NCR_PRINT(NDEBUG_ANY);
	NCR_PRINT_PHASE(NDEBUG_ANY);

	pr_bfr = (char *)__get_free_page(GFP_ATOMIC);
	if (!pr_bfr) {
		printk("NCR5380_print_status: no memory for print buffer\n");
		return;
	}
	len = NCR5380_proc_info(instance, pr_bfr, &start, 0, PAGE_SIZE, 0);
	pr_bfr[len] = 0;
	printk("\n%s\n", pr_bfr);
	free_page((unsigned long)pr_bfr);
}


/******************************************/
/*
 * /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
*/

#undef SPRINTF
#define SPRINTF(fmt,args...)							\
	do {									\
		if (pos + strlen(fmt) + 20 /* slop */ < buffer + length)	\
			pos += sprintf(pos, fmt , ## args);			\
	} while(0)
static char *lprint_Scsi_Cmnd(Scsi_Cmnd *cmd, char *pos, char *buffer, int length);

static int NCR5380_proc_info(struct Scsi_Host *instance, char *buffer,
			     char **start, off_t offset, int length, int inout)
{
	char *pos = buffer;
	struct NCR5380_hostdata *hostdata;
	Scsi_Cmnd *ptr;
	unsigned long flags;
	off_t begin = 0;
#define check_offset()					\
	do {						\
		if (pos - buffer < offset - begin) {	\
			begin += pos - buffer;		\
			pos = buffer;			\
		}					\
	} while (0)

	hostdata = (struct NCR5380_hostdata *)instance->hostdata;

	if (inout)			/* Has data been written to the file ? */
		return -ENOSYS;		/* Currently this is a no-op */
	SPRINTF("NCR5380 core release=%d.\n", NCR5380_PUBLIC_RELEASE);
	check_offset();
	local_irq_save(flags);
	SPRINTF("NCR5380: coroutine is%s running.\n",
		main_running ? "" : "n't");
	check_offset();
	if (!hostdata->connected)
		SPRINTF("scsi%d: no currently connected command\n", HOSTNO);
	else
		pos = lprint_Scsi_Cmnd((Scsi_Cmnd *) hostdata->connected,
				       pos, buffer, length);
	SPRINTF("scsi%d: issue_queue\n", HOSTNO);
	check_offset();
	for (ptr = (Scsi_Cmnd *)hostdata->issue_queue; ptr; ptr = NEXT(ptr)) {
		pos = lprint_Scsi_Cmnd(ptr, pos, buffer, length);
		check_offset();
	}

	SPRINTF("scsi%d: disconnected_queue\n", HOSTNO);
	check_offset();
	for (ptr = (Scsi_Cmnd *) hostdata->disconnected_queue; ptr;
	     ptr = NEXT(ptr)) {
		pos = lprint_Scsi_Cmnd(ptr, pos, buffer, length);
		check_offset();
	}

	local_irq_restore(flags);
	*start = buffer + (offset - begin);
	if (pos - buffer < offset - begin)
		return 0;
	else if (pos - buffer - (offset - begin) < length)
		return pos - buffer - (offset - begin);
	return length;
}

static char *lprint_Scsi_Cmnd(Scsi_Cmnd *cmd, char *pos, char *buffer, int length)
{
	int i, s;
	unsigned char *command;
	SPRINTF("scsi%d: destination target %d, lun %d\n",
		H_NO(cmd), cmd->device->id, cmd->device->lun);
	SPRINTF("        command = ");
	command = cmd->cmnd;
	SPRINTF("%2d (0x%02x)", command[0], command[0]);
	for (i = 1, s = COMMAND_SIZE(command[0]); i < s; ++i)
		SPRINTF(" %02x", command[i]);
	SPRINTF("\n");
	return pos;
}


/*
 * Function : void NCR5380_init (struct Scsi_Host *instance)
 *
 * Purpose : initializes *instance and corresponding 5380 chip.
 *
 * Inputs : instance - instantiation of the 5380 driver.
 *
 * Notes : I assume that the host, hostno, and id bits have been
 *	set correctly.  I don't care about the irq and other fields.
 *
 */

static int __init NCR5380_init(struct Scsi_Host *instance, int flags)
{
	int i;
	SETUP_HOSTDATA(instance);

	NCR5380_all_init();

	hostdata->aborted = 0;
	hostdata->id_mask = 1 << instance->this_id;
	hostdata->id_higher_mask = 0;
	for (i = hostdata->id_mask; i <= 0x80; i <<= 1)
		if (i > hostdata->id_mask)
			hostdata->id_higher_mask |= i;
	for (i = 0; i < 8; ++i)
		hostdata->busy[i] = 0;
#ifdef SUPPORT_TAGS
	init_tags();
#endif
#if defined (REAL_DMA)
	hostdata->dma_len = 0;
#endif
	hostdata->targets_present = 0;
	hostdata->connected = NULL;
	hostdata->issue_queue = NULL;
	hostdata->disconnected_queue = NULL;
	hostdata->flags = FLAG_CHECK_LAST_BYTE_SENT;

	if (!the_template) {
		the_template = instance->hostt;
		first_instance = instance;
	}

#ifndef AUTOSENSE
	if ((instance->cmd_per_lun > 1) || (instance->can_queue > 1))
		printk("scsi%d: WARNING : support for multiple outstanding commands enabled\n"
		       "        without AUTOSENSE option, contingent allegiance conditions may\n"
		       "        be incorrectly cleared.\n", HOSTNO);
#endif /* def AUTOSENSE */

	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);

	return 0;
}

/*
 * Function : int NCR5380_queue_command (Scsi_Cmnd *cmd,
 *	void (*done)(Scsi_Cmnd *))
 *
 * Purpose :  enqueues a SCSI command
 *
 * Inputs : cmd - SCSI command, done - function called on completion, with
 *	a pointer to the command descriptor.
 *
 * Returns : 0
 *
 * Side effects :
 *      cmd is added to the per instance issue_queue, with minor
 *	twiddling done to the host specific fields of cmd.  If the
 *	main coroutine is not running, it is restarted.
 *
 */

static int NCR5380_queue_command(Scsi_Cmnd *cmd, void (*done)(Scsi_Cmnd *))
{
	SETUP_HOSTDATA(cmd->device->host);
	Scsi_Cmnd *tmp;
	int oldto;
	unsigned long flags;

#if (NDEBUG & NDEBUG_NO_WRITE)
	switch (cmd->cmnd[0]) {
	case WRITE_6:
	case WRITE_10:
		printk(KERN_NOTICE "scsi%d: WRITE attempted with NO_WRITE debugging flag set\n",
		       H_NO(cmd));
		cmd->result = (DID_ERROR << 16);
		done(cmd);
		return 0;
	}
#endif /* (NDEBUG & NDEBUG_NO_WRITE) */

#ifdef NCR5380_STATS
# if 0
	if (!hostdata->connected && !hostdata->issue_queue &&
	    !hostdata->disconnected_queue) {
		hostdata->timebase = jiffies;
	}
# endif
# ifdef NCR5380_STAT_LIMIT
	if (scsi_bufflen(cmd) > NCR5380_STAT_LIMIT)
# endif
		switch (cmd->cmnd[0]) {
		case WRITE:
		case WRITE_6:
		case WRITE_10:
			hostdata->time_write[cmd->device->id] -= (jiffies - hostdata->timebase);
			hostdata->bytes_write[cmd->device->id] += scsi_bufflen(cmd);
			hostdata->pendingw++;
			break;
		case READ:
		case READ_6:
		case READ_10:
			hostdata->time_read[cmd->device->id] -= (jiffies - hostdata->timebase);
			hostdata->bytes_read[cmd->device->id] += scsi_bufflen(cmd);
			hostdata->pendingr++;
			break;
		}
#endif

	/*
	 * We use the host_scribble field as a pointer to the next command
	 * in a queue
	 */

	SET_NEXT(cmd, NULL);
	cmd->scsi_done = done;

	cmd->result = 0;

	/*
	 * 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.
	 */

	local_irq_save(flags);
	/* ++guenther: now that the issue queue is being set up, we can lock ST-DMA.
	 * Otherwise a running NCR5380_main may steal the lock.
	 * Lock before actually inserting due to fairness reasons explained in
	 * atari_scsi.c. If we insert first, then it's impossible for this driver
	 * to release the lock.
	 * Stop timer for this command while waiting for the lock, or timeouts
	 * may happen (and they really do), and it's no good if the command doesn't
	 * appear in any of the queues.
	 * ++roman: Just disabling the NCR interrupt isn't sufficient here,
	 * because also a timer int can trigger an abort or reset, which would
	 * alter queues and touch the lock.
	 */
	if (!IS_A_TT()) {
		/* perhaps stop command timer here */
		falcon_get_lock();
		/* perhaps restart command timer here */
	}
	if (!(hostdata->issue_queue) || (cmd->cmnd[0] == REQUEST_SENSE)) {
		LIST(cmd, hostdata->issue_queue);
		SET_NEXT(cmd, hostdata->issue_queue);
		hostdata->issue_queue = cmd;
	} else {
		for (tmp = (Scsi_Cmnd *)hostdata->issue_queue;
		     NEXT(tmp); tmp = NEXT(tmp))
			;
		LIST(cmd, tmp);
		SET_NEXT(tmp, cmd);
	}
	local_irq_restore(flags);

	QU_PRINTK("scsi%d: command added to %s of queue\n", H_NO(cmd),
		  (cmd->cmnd[0] == REQUEST_SENSE) ? "head" : "tail");

	/* If queue_command() is called from an interrupt (real one or bottom
	 * half), we let queue_main() do the job of taking care about main. If it
	 * is already running, this is a no-op, else main will be queued.
	 *
	 * If we're not in an interrupt, we can call NCR5380_main()
	 * unconditionally, because it cannot be already running.
	 */
	if (in_interrupt() || ((flags >> 8) & 7) >= 6)
		queue_main();
	else
		NCR5380_main(NULL);
	return 0;
}

/*
 * Function : NCR5380_main (void)
 *
 * Purpose : 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.
 *
 * NOTE : NCR5380_main exits with interrupts *disabled*, the caller should
 *  reenable them.  This prevents reentrancy and kernel stack overflow.
 */

static void NCR5380_main(struct work_struct *work)
{
	Scsi_Cmnd *tmp, *prev;
	struct Scsi_Host *instance = first_instance;
	struct NCR5380_hostdata *hostdata = HOSTDATA(instance);
	int done;
	unsigned long flags;

	/*
	 * We run (with interrupts disabled) until we're sure that none of
	 * the host adapters have anything that can be done, at which point
	 * we set main_running to 0 and exit.
	 *
	 * Interrupts are enabled before doing various other internal
	 * instructions, after we've decided that we need to run through
	 * the loop again.
	 *
	 * this should prevent any race conditions.
	 *
	 * ++roman: Just disabling the NCR interrupt isn't sufficient here,
	 * because also a timer int can trigger an abort or reset, which can
	 * alter queues and touch the Falcon lock.
	 */

	/* Tell int handlers main() is now already executing.  Note that
	   no races are possible here. If an int comes in before
	   'main_running' is set here, and queues/executes main via the
	   task queue, it doesn't do any harm, just this instance of main
	   won't find any work left to do. */
	if (main_running)
		return;
	main_running = 1;

	local_save_flags(flags);
	do {
		local_irq_disable();	/* Freeze request queues */
		done = 1;

		if (!hostdata->connected) {
			MAIN_PRINTK("scsi%d: not connected\n", HOSTNO);
			/*
			 * Search through the issue_queue for a command destined
			 * for a target that's not busy.
			 */
#if (NDEBUG & NDEBUG_LISTS)
			for (tmp = (Scsi_Cmnd *) hostdata->issue_queue, prev = NULL;
			     tmp && (tmp != prev); prev = tmp, tmp = NEXT(tmp))
				;
			/*printk("%p  ", tmp);*/
			if ((tmp == prev) && tmp)
				printk(" LOOP\n");
			/* else printk("\n"); */
#endif
			for (tmp = (Scsi_Cmnd *) hostdata->issue_queue,
			     prev = NULL; tmp; prev = tmp, tmp = NEXT(tmp)) {

#if (NDEBUG & NDEBUG_LISTS)
				if (prev != tmp)
					printk("MAIN tmp=%p   target=%d   busy=%d lun=%d\n",
					       tmp, tmp->device->id, hostdata->busy[tmp->device->id],
					       tmp->device->lun);
#endif
				/*  When we find one, remove it from the issue queue. */
				/* ++guenther: possible race with Falcon locking */
				if (
#ifdef SUPPORT_TAGS
				    !is_lun_busy( tmp, tmp->cmnd[0] != REQUEST_SENSE)
#else
				    !(hostdata->busy[tmp->device->id] & (1 << tmp->device->lun))
#endif
				    ) {
					/* ++guenther: just to be sure, this must be atomic */
					local_irq_disable();
					if (prev) {
						REMOVE(prev, NEXT(prev), tmp, NEXT(tmp));
						SET_NEXT(prev, NEXT(tmp));
					} else {
						REMOVE(-1, hostdata->issue_queue, tmp, NEXT(tmp));
						hostdata->issue_queue = NEXT(tmp);
					}
					SET_NEXT(tmp, NULL);
					falcon_dont_release++;

					/* reenable interrupts after finding one */
					local_irq_restore(flags);

					/*
					 * 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.
					 */
					MAIN_PRINTK("scsi%d: main(): command for target %d "
						    "lun %d removed from issue_queue\n",
						    HOSTNO, tmp->device->id, tmp->device->lun);
					/*
					 * REQUEST SENSE commands are issued without tagged
					 * queueing, even on SCSI-II devices because the
					 * contingent allegiance condition exists for the
					 * entire unit.
					 */
					/* ++roman: ...and the standard also requires that
					 * REQUEST SENSE command are untagged.
					 */

#ifdef SUPPORT_TAGS
					cmd_get_tag(tmp, tmp->cmnd[0] != REQUEST_SENSE);
#endif
					if (!NCR5380_select(instance, tmp,
					    (tmp->cmnd[0] == REQUEST_SENSE) ? TAG_NONE :
					    TAG_NEXT)) {
						falcon_dont_release--;
						/* release if target did not response! */
						falcon_release_lock_if_possible(hostdata);
						break;
					} else {
						local_irq_disable();
						LIST(tmp, hostdata->issue_queue);
						SET_NEXT(tmp, hostdata->issue_queue);
						hostdata->issue_queue = tmp;
#ifdef SUPPORT_TAGS
						cmd_free_tag(tmp);
#endif
						falcon_dont_release--;
						local_irq_restore(flags);
						MAIN_PRINTK("scsi%d: main(): select() failed, "
							    "returned to issue_queue\n", HOSTNO);
						if (hostdata->connected)
							break;
					}
				} /* if target/lun/target queue is not busy */
			} /* for issue_queue */
		} /* if (!hostdata->connected) */

		if (hostdata->connected
#ifdef REAL_DMA
		    && !hostdata->dma_len
#endif
		    ) {
			local_irq_restore(flags);
			MAIN_PRINTK("scsi%d: main: performing information transfer\n",
				    HOSTNO);
			NCR5380_information_transfer(instance);
			MAIN_PRINTK("scsi%d: main: done set false\n", HOSTNO);
			done = 0;
		}
	} while (!done);

	/* Better allow ints _after_ 'main_running' has been cleared, else
	   an interrupt could believe we'll pick up the work it left for
	   us, but we won't see it anymore here... */
	main_running = 0;
	local_irq_restore(flags);
}


#ifdef REAL_DMA
/*
 * 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.
 *
 */

static void NCR5380_dma_complete(struct Scsi_Host *instance)
{
	SETUP_HOSTDATA(instance);
	int transfered, saved_data = 0, overrun = 0, cnt, toPIO;
	unsigned char **data, p;
	volatile int *count;

	if (!hostdata->connected) {
		printk(KERN_WARNING "scsi%d: received end of DMA interrupt with "
		       "no connected cmd\n", HOSTNO);
		return;
	}

	if (atari_read_overruns) {
		p = hostdata->connected->SCp.phase;
		if (p & SR_IO) {
			udelay(10);
			if ((NCR5380_read(BUS_AND_STATUS_REG) &
			     (BASR_PHASE_MATCH|BASR_ACK)) ==
			    (BASR_PHASE_MATCH|BASR_ACK)) {
				saved_data = NCR5380_read(INPUT_DATA_REG);
				overrun = 1;
				DMA_PRINTK("scsi%d: read overrun handled\n", HOSTNO);
			}
		}
	}

	DMA_PRINTK("scsi%d: real DMA transfer complete, basr 0x%X, sr 0x%X\n",
		   HOSTNO, NCR5380_read(BUS_AND_STATUS_REG),
		   NCR5380_read(STATUS_REG));

	(void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
	NCR5380_write(MODE_REG, MR_BASE);
	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);

	transfered = hostdata->dma_len - NCR5380_dma_residual(instance);
	hostdata->dma_len = 0;

	data = (unsigned char **)&hostdata->connected->SCp.ptr;
	count = &hostdata->connected->SCp.this_residual;
	*data += transfered;
	*count -= transfered;

	if (atari_read_overruns) {
		if ((NCR5380_read(STATUS_REG) & PHASE_MASK) == p && (p & SR_IO)) {
			cnt = toPIO = atari_read_overruns;
			if (overrun) {
				DMA_PRINTK("Got an input overrun, using saved byte\n");
				*(*data)++ = saved_data;
				(*count)--;
				cnt--;
				toPIO--;
			}
			DMA_PRINTK("Doing %d-byte PIO to 0x%08lx\n", cnt, (long)*data);
			NCR5380_transfer_pio(instance, &p, &cnt, data);
			*count -= toPIO - cnt;
		}
	}
}
#endif /* REAL_DMA */


/*
 * Function : void NCR5380_intr (int irq)
 *
 * Purpose : handle interrupts, reestablishing I_T_L or I_T_L_Q nexuses
 *	from the disconnected queue, and restarting NCR5380_main()
 *	as required.
 *
 * Inputs : int irq, irq that caused this interrupt.
 *
 */

static irqreturn_t NCR5380_intr(int irq, void *dev_id)
{
	struct Scsi_Host *instance = first_instance;
	int done = 1, handled = 0;
	unsigned char basr;

	INT_PRINTK("scsi%d: NCR5380 irq triggered\n", HOSTNO);

	/* Look for pending interrupts */
	basr = NCR5380_read(BUS_AND_STATUS_REG);
	INT_PRINTK("scsi%d: BASR=%02x\n", HOSTNO, basr);
	/* dispatch to appropriate routine if found and done=0 */
	if (basr & BASR_IRQ) {
		NCR_PRINT(NDEBUG_INTR);
		if ((NCR5380_read(STATUS_REG) & (SR_SEL|SR_IO)) == (SR_SEL|SR_IO)) {
			done = 0;
			ENABLE_IRQ();
			INT_PRINTK("scsi%d: SEL interrupt\n", HOSTNO);
			NCR5380_reselect(instance);
			(void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
		} else if (basr & BASR_PARITY_ERROR) {
			INT_PRINTK("scsi%d: PARITY interrupt\n", HOSTNO);
			(void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
		} else if ((NCR5380_read(STATUS_REG) & SR_RST) == SR_RST) {
			INT_PRINTK("scsi%d: RESET interrupt\n", HOSTNO);
			(void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
		} else {
			/*
			 * The rest of the interrupt conditions can occur only during a
			 * DMA transfer
			 */

#if defined(REAL_DMA)
			/*
			 * We should only get PHASE MISMATCH and EOP interrupts if we have
			 * DMA enabled, so do a sanity check based on the current setting
			 * of the MODE register.
			 */

			if ((NCR5380_read(MODE_REG) & MR_DMA_MODE) &&
			    ((basr & BASR_END_DMA_TRANSFER) ||
			     !(basr & BASR_PHASE_MATCH))) {

				INT_PRINTK("scsi%d: PHASE MISM or EOP interrupt\n", HOSTNO);
				NCR5380_dma_complete( instance );
				done = 0;
				ENABLE_IRQ();
			} else
#endif /* REAL_DMA */
			{
/* MS: Ignore unknown phase mismatch interrupts (caused by EOP interrupt) */
				if (basr & BASR_PHASE_MATCH)
					printk(KERN_NOTICE "scsi%d: unknown interrupt, "
					       "BASR 0x%x, MR 0x%x, SR 0x%x\n",
					       HOSTNO, basr, NCR5380_read(MODE_REG),
					       NCR5380_read(STATUS_REG));
				(void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
			}
		} /* if !(SELECTION || PARITY) */
		handled = 1;
	} /* BASR & IRQ */ else {
		printk(KERN_NOTICE "scsi%d: interrupt without IRQ bit set in BASR, "
		       "BASR 0x%X, MR 0x%X, SR 0x%x\n", HOSTNO, basr,
		       NCR5380_read(MODE_REG), NCR5380_read(STATUS_REG));
		(void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
	}

	if (!done) {
		INT_PRINTK("scsi%d: in int routine, calling main\n", HOSTNO);
		/* Put a call to NCR5380_main() on the queue... */
		queue_main();
	}
	return IRQ_RETVAL(handled);
}

#ifdef NCR5380_STATS
static void collect_stats(struct NCR5380_hostdata* hostdata, Scsi_Cmnd *cmd)
{
# ifdef NCR5380_STAT_LIMIT
	if (scsi_bufflen(cmd) > NCR5380_STAT_LIMIT)
# endif
		switch (cmd->cmnd[0]) {
		case WRITE:
		case WRITE_6:
		case WRITE_10:
			hostdata->time_write[cmd->device->id] += (jiffies - hostdata->timebase);
			/*hostdata->bytes_write[cmd->device->id] += scsi_bufflen(cmd);*/
			hostdata->pendingw--;
			break;
		case READ:
		case READ_6:
		case READ_10:
			hostdata->time_read[cmd->device->id] += (jiffies - hostdata->timebase);
			/*hostdata->bytes_read[cmd->device->id] += scsi_bufflen(cmd);*/
			hostdata->pendingr--;
			break;
		}
}
#endif

/*
 * Function : int NCR5380_select (struct Scsi_Host *instance, Scsi_Cmnd *cmd,
 *	int tag);
 *
 * 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
 *	target lives, cmd - SCSI command to execute, tag - set to TAG_NEXT for
 *	new tag, TAG_NONE for untagged queueing, otherwise set to the tag for
 *	the command that is presently connected.
 *
 * Returns : -1 if selection could not execute for some reason,
 *	0 if selection succeeded or failed because the target
 *	did not respond.
 *
 * 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.
 */

static int NCR5380_select(struct Scsi_Host *instance, Scsi_Cmnd *cmd, int tag)
{
	SETUP_HOSTDATA(instance);
	unsigned char tmp[3], phase;
	unsigned char *data;
	int len;
	unsigned long timeout;
	unsigned long flags;

	hostdata->restart_select = 0;
	NCR_PRINT(NDEBUG_ARBITRATION);
	ARB_PRINTK("scsi%d: starting arbitration, id = %d\n", HOSTNO,
		   instance->this_id);

	/*
	 * Set the phase bits to 0, otherwise the NCR5380 won't drive the
	 * data bus during SELECTION.
	 */

	local_irq_save(flags);
	if (hostdata->connected) {
		local_irq_restore(flags);
		return -1;
	}
	NCR5380_write(TARGET_COMMAND_REG, 0);

	/*
	 * Start arbitration.
	 */

	NCR5380_write(OUTPUT_DATA_REG, hostdata->id_mask);
	NCR5380_write(MODE_REG, MR_ARBITRATE);

	local_irq_restore(flags);

	/* Wait for arbitration logic to complete */
#if defined(NCR_TIMEOUT)
	{
		unsigned long timeout = jiffies + 2*NCR_TIMEOUT;

		while (!(NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_PROGRESS) &&
		       time_before(jiffies, timeout) && !hostdata->connected)
			;
		if (time_after_eq(jiffies, timeout)) {
			printk("scsi : arbitration timeout at %d\n", __LINE__);
			NCR5380_write(MODE_REG, MR_BASE);
			NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
			return -1;
		}
	}
#else /* NCR_TIMEOUT */
	while (!(NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_PROGRESS) &&
	       !hostdata->connected)
		;
#endif

	ARB_PRINTK("scsi%d: arbitration complete\n", HOSTNO);

	if (hostdata->connected) {
		NCR5380_write(MODE_REG, MR_BASE);
		return -1;
	}
	/*
	 * The arbitration delay is 2.2us, but this is a minimum and there is
	 * no maximum so we can safely sleep for ceil(2.2) usecs to accommodate
	 * the integral nature of udelay().
	 *
	 */

	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) ||
	    hostdata->connected) {
		NCR5380_write(MODE_REG, MR_BASE);
		ARB_PRINTK("scsi%d: lost arbitration, deasserting MR_ARBITRATE\n",
			   HOSTNO);
		return -1;
	}

	/* 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);

	if ((NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST) ||
	    hostdata->connected) {
		NCR5380_write(MODE_REG, MR_BASE);
		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
		ARB_PRINTK("scsi%d: lost arbitration, deasserting ICR_ASSERT_SEL\n",
			   HOSTNO);
		return -1;
	}

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

#ifdef CONFIG_ATARI_SCSI_TOSHIBA_DELAY
	/* ++roman: But some targets (see above :-) seem to need a bit more... */
	udelay(15);
#else
	udelay(2);
#endif

	if (hostdata->connected) {
		NCR5380_write(MODE_REG, MR_BASE);
		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
		return -1;
	}

	ARB_PRINTK("scsi%d: won arbitration\n", HOSTNO);

	/*
	 * Now that we have won arbitration, start Selection process, asserting
	 * the host and target ID's on the SCSI bus.
	 */

	NCR5380_write(OUTPUT_DATA_REG, (hostdata->id_mask | (1 << cmd->device->id)));

	/*
	 * 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.
	 */

	if (hostdata->connected) {
		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
		return -1;
	}

	NCR5380_write(SELECT_ENABLE_REG, 0);

	/*
	 * 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);

	SEL_PRINTK("scsi%d: selecting target %d\n", HOSTNO, cmd->device->id);

	/*
	 * The SCSI specification calls for a 250 ms timeout for the actual
	 * selection.
	 */

	timeout = jiffies + 25;

	/*
	 * XXX very interesting - we're seeing a bounce where the BSY we
	 * asserted is being reflected / still asserted (propagation delay?)
	 * and it's detecting as true.  Sigh.
	 */

#if 0
	/* ++roman: If a target conformed to the SCSI standard, it wouldn't assert
	 * IO while SEL is true. But again, there are some disks out the in the
	 * world that do that nevertheless. (Somebody claimed that this announces
	 * reselection capability of the target.) So we better skip that test and
	 * only wait for BSY... (Famous german words: Der Klügere gibt nach :-)
	 */

	while (time_before(jiffies, timeout) &&
	       !(NCR5380_read(STATUS_REG) & (SR_BSY | SR_IO)))
		;

	if ((NCR5380_read(STATUS_REG) & (SR_SEL | SR_IO)) == (SR_SEL | SR_IO)) {
		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
		NCR5380_reselect(instance);
		printk(KERN_ERR "scsi%d: reselection after won arbitration?\n",
		       HOSTNO);
		NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
		return -1;
	}
#else
	while (time_before(jiffies, timeout) && !(NCR5380_read(STATUS_REG) & SR_BSY))
		;
#endif

	/*
	 * 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);

	if (!(NCR5380_read(STATUS_REG) & SR_BSY)) {
		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
		if (hostdata->targets_present & (1 << cmd->device->id)) {
			printk(KERN_ERR "scsi%d: weirdness\n", HOSTNO);
			if (hostdata->restart_select)
				printk(KERN_NOTICE "\trestart select\n");
			NCR_PRINT(NDEBUG_ANY);
			NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
			return -1;
		}
		cmd->result = DID_BAD_TARGET << 16;
#ifdef NCR5380_STATS
		collect_stats(hostdata, cmd);
#endif
#ifdef SUPPORT_TAGS
		cmd_free_tag(cmd);
#endif
		cmd->scsi_done(cmd);
		NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
		SEL_PRINTK("scsi%d: target did not respond within 250ms\n", HOSTNO);
		NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
		return 0;
	}

	hostdata->targets_present |= (1 << cmd->device->id);

	/*
	 * 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 */
	while (!(NCR5380_read(STATUS_REG) & SR_REQ))
		;

	SEL_PRINTK("scsi%d: target %d selected, going into MESSAGE OUT phase.\n",
		   HOSTNO, cmd->device->id);
	tmp[0] = IDENTIFY(1, cmd->device->lun);

#ifdef SUPPORT_TAGS
	if (cmd->tag != TAG_NONE) {
		tmp[1] = hostdata->last_message = SIMPLE_QUEUE_TAG;
		tmp[2] = cmd->tag;
		len = 3;
	} else
		len = 1;
#else
	len = 1;
	cmd->tag = 0;
#endif /* SUPPORT_TAGS */

	/* Send message(s) */
	data = tmp;
	phase = PHASE_MSGOUT;
	NCR5380_transfer_pio(instance, &phase, &len, &data);
	SEL_PRINTK("scsi%d: nexus established.\n", HOSTNO);
	/* XXX need to handle errors here */
	hostdata->connected = cmd;
#ifndef SUPPORT_TAGS
	hostdata->busy[cmd->device->id] |= (1 << cmd->device->lun);
#endif

	initialize_SCp(cmd);

	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
 *	maximum number of bytes, 0 if all bytes are transfered or exit
 *	is in same phase.
 *
 *	Also, *phase, *count, *data are modified in place.
 *
 * XXX Note : handling for bus free may be useful.
 */

/*
 * Note : this code is not as quick as it could be, however it
 * IS 100% reliable, and for the actual data transfer where speed
 * counts, we will always do a pseudo DMA or DMA transfer.
 */

static int NCR5380_transfer_pio(struct Scsi_Host *instance,
				unsigned char *phase, int *count,
				unsigned char **data)
{
	register unsigned char p = *phase, tmp;
	register int c = *count;
	register unsigned char *d = *data;

	/*
	 * The NCR5380 chip will only drive the SCSI bus when the
	 * phase specified in the appropriate bits of the TARGET COMMAND
	 * REGISTER match the STATUS REGISTER
	 */

	NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(p));

	do {
		/*
		 * Wait for assertion of REQ, after which the phase bits will be
		 * valid
		 */
		while (!((tmp = NCR5380_read(STATUS_REG)) & SR_REQ))
			;

		HSH_PRINTK("scsi%d: REQ detected\n", HOSTNO);

		/* Check for phase mismatch */
		if ((tmp & PHASE_MASK) != p) {
			PIO_PRINTK("scsi%d: phase mismatch\n", HOSTNO);
			NCR_PRINT_PHASE(NDEBUG_PIO);
			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);
				NCR_PRINT(NDEBUG_PIO);
				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);
				NCR_PRINT(NDEBUG_PIO);
				NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE |
					      ICR_ASSERT_DATA | ICR_ASSERT_ATN | ICR_ASSERT_ACK);
			}
		} else {
			NCR_PRINT(NDEBUG_PIO);
			NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ACK);
		}

		while (NCR5380_read(STATUS_REG) & SR_REQ)
			;

		HSH_PRINTK("scsi%d: req false, handshake complete\n", HOSTNO);

		/*
		 * 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);

	PIO_PRINTK("scsi%d: residual %d\n", HOSTNO, c);

	*count = c;
	*data = d;
	tmp = NCR5380_read(STATUS_REG);
	/* The phase read from the bus is valid if either REQ is (already)
	 * asserted or if ACK hasn't been released yet. The latter is the case if
	 * we're in MSGIN and all wanted bytes have been received.
	 */
	if ((tmp & SR_REQ) || (p == PHASE_MSGIN && c == 0))
		*phase = tmp & PHASE_MASK;
	else
		*phase = PHASE_UNKNOWN;

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

/*
 * Function : do_abort (Scsi_Host *host)
 *
 * Purpose : abort the currently established nexus.  Should only be
 *	called from a routine which can drop into a
 *
 * Returns : 0 on success, -1 on failure.
 */

static int do_abort(struct Scsi_Host *host)
{
	unsigned char tmp, *msgptr, phase;
	int len;

	/* 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.
	 */

	while (!((tmp = NCR5380_read(STATUS_REG)) & SR_REQ))
		;

	NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(tmp));

	if ((tmp & PHASE_MASK) != PHASE_MSGOUT) {
		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);
	}

	tmp = ABORT;
	msgptr = &tmp;
	len = 1;
	phase = PHASE_MSGOUT;
	NCR5380_transfer_pio(host, &phase, &len, &msgptr);

	/*
	 * If we got here, and the command completed successfully,
	 * we're about to go into bus free state.
	 */

	return len ? -1 : 0;
}

#if defined(REAL_DMA)
/*
 * Function : int NCR5380_transfer_dma (struct Scsi_Host *instance,
 *      unsigned char *phase, int *count, unsigned char **data)
 *
 * Purpose : transfers data in given phase using either real
 *	or pseudo DMA.
 *
 * Inputs : instance - instance of driver, *phase - pointer to
 *	what phase is expected, *count - pointer to number of
 *	bytes to transfer, **data - pointer to data pointer.
 *
 * Returns : -1 when different phase is entered without transferring
 *	maximum number of bytes, 0 if all bytes or transfered or exit
 *	is in same phase.
 *
 *	Also, *phase, *count, *data are modified in place.
 *
 */


static int NCR5380_transfer_dma(struct Scsi_Host *instance,
				unsigned char *phase, int *count,
				unsigned char **data)
{
	SETUP_HOSTDATA(instance);
	register int c = *count;
	register unsigned char p = *phase;
	register unsigned char *d = *data;
	unsigned char tmp;
	unsigned long flags;

	if ((tmp = (NCR5380_read(STATUS_REG) & PHASE_MASK)) != p) {
		*phase = tmp;
		return -1;
	}

	if (atari_read_overruns && (p & SR_IO))
		c -= atari_read_overruns;

	DMA_PRINTK("scsi%d: initializing DMA for %s, %d bytes %s %p\n",
		   HOSTNO, (p & SR_IO) ? "reading" : "writing",
		   c, (p & SR_IO) ? "to" : "from", d);

	NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(p));

#ifdef REAL_DMA
	NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE | MR_ENABLE_EOP_INTR | MR_MONITOR_BSY);
#endif /* def REAL_DMA  */

	if (IS_A_TT()) {
		/* On the Medusa, it is a must to initialize the DMA before
		 * starting the NCR. This is also the cleaner way for the TT.
		 */
		local_irq_save(flags);
		hostdata->dma_len = (p & SR_IO) ?
			NCR5380_dma_read_setup(instance, d, c) :
			NCR5380_dma_write_setup(instance, d, c);
		local_irq_restore(flags);
	}

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

	if (!IS_A_TT()) {
		/* On the Falcon, the DMA setup must be done after the last */
		/* NCR access, else the DMA setup gets trashed!
		 */
		local_irq_save(flags);
		hostdata->dma_len = (p & SR_IO) ?
			NCR5380_dma_read_setup(instance, d, c) :
			NCR5380_dma_write_setup(instance, d, c);
		local_irq_restore(flags);
	}
	return 0;
}
#endif /* defined(REAL_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.
 */

static void NCR5380_information_transfer(struct Scsi_Host *instance)
{
	SETUP_HOSTDATA(instance);
	unsigned long flags;
	unsigned char msgout = NOP;
	int sink = 0;
	int len;
#if defined(REAL_DMA)
	int transfersize;
#endif
	unsigned char *data;
	unsigned char phase, tmp, extended_msg[10], old_phase = 0xff;
	Scsi_Cmnd *cmd = (Scsi_Cmnd *) hostdata->connected;

	while (1) {
		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;
				NCR_PRINT_PHASE(NDEBUG_INFORMATION);
			}

			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", HOSTNO);
				sink = 1;
				do_abort(instance);
				cmd->result = DID_ERROR << 16;
				cmd->scsi_done(cmd);
				return;
#endif
			case PHASE_DATAIN:
				/*
				 * If there is no room left in the current buffer in the
				 * scatter-gather list, move onto the next one.
				 */

				if (!cmd->SCp.this_residual && cmd->SCp.buffers_residual) {
					++cmd->SCp.buffer;
					--cmd->SCp.buffers_residual;
					cmd->SCp.this_residual = cmd->SCp.buffer->length;
					cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
					/* ++roman: Try to merge some scatter-buffers if
					 * they are at contiguous physical addresses.
					 */
					merge_contiguous_buffers(cmd);
					INF_PRINTK("scsi%d: %d bytes and %d buffers left\n",
						   HOSTNO, cmd->SCp.this_residual,
						   cmd->SCp.buffers_residual);
				}

				/*
				 * 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.
				 */

				/* ++roman: I suggest, this should be
				 *   #if def(REAL_DMA)
				 * instead of leaving REAL_DMA out.
				 */

#if defined(REAL_DMA)
				if (!cmd->device->borken &&
				    (transfersize = NCR5380_dma_xfer_len(instance,cmd,phase)) > 31) {
					len = transfersize;
					cmd->SCp.phase = phase;
					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. */
						printk(KERN_NOTICE "scsi%d: switching target %d "
							   "lun %d to slow handshake\n", HOSTNO,
							   cmd->device->id, cmd->device->lun);
						cmd->device->borken = 1;
						NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE |
							ICR_ASSERT_ATN);
						sink = 1;
						do_abort(instance);
						cmd->result = DID_ERROR << 16;
						cmd->scsi_done(cmd);
						/* XXX - need to source or sink data here, as appropriate */
					} else {
#ifdef REAL_DMA
						/* ++roman: When using real DMA,
						 * information_transfer() should return after
						 * starting DMA since it has nothing more to
						 * do.
						 */
						return;
#else
						cmd->SCp.this_residual -= transfersize - len;
#endif
					}
				} else
#endif /* defined(REAL_DMA) */
					NCR5380_transfer_pio(instance, &phase,
							     (int *)&cmd->SCp.this_residual,
							     (unsigned char **)&cmd->SCp.ptr);
				break;
			case PHASE_MSGIN:
				len = 1;
				data = &tmp;
				NCR5380_write(SELECT_ENABLE_REG, 0);	/* disable reselects */
				NCR5380_transfer_pio(instance, &phase, &len, &data);
				cmd->SCp.Message = tmp;

				switch (tmp) {
				/*
				 * Linking lets us reduce the time required to get the
				 * next command out to the device, hopefully this will
				 * mean we don't waste another revolution due to the delays
				 * required by ARBITRATION and another SELECTION.
				 *
				 * In the current implementation proposal, low level drivers
				 * merely have to start the next command, pointed to by
				 * next_link, done() is called as with unlinked commands.
				 */
#ifdef LINKED
				case LINKED_CMD_COMPLETE:
				case LINKED_FLG_CMD_COMPLETE:
					/* Accept message by clearing ACK */
					NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);

					LNK_PRINTK("scsi%d: target %d lun %d linked command "
						   "complete.\n", HOSTNO, cmd->device->id, cmd->device->lun);

					/* Enable reselect interrupts */
					NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
					/*
					 * Sanity check : A linked command should only terminate
					 * with one of these messages if there are more linked
					 * commands available.
					 */

					if (!cmd->next_link) {
						 printk(KERN_NOTICE "scsi%d: target %d lun %d "
							"linked command complete, no next_link\n",
							HOSTNO, cmd->device->id, cmd->device->lun);
						sink = 1;
						do_abort(instance);
						return;
					}

					initialize_SCp(cmd->next_link);
					/* The next command is still part of this process; copy it
					 * and don't free it! */
					cmd->next_link->tag = cmd->tag;
					cmd->result = cmd->SCp.Status | (cmd->SCp.Message << 8);
					LNK_PRINTK("scsi%d: target %d lun %d linked request "
						   "done, calling scsi_done().\n",
						   HOSTNO, cmd->device->id, cmd->device->lun);
#ifdef NCR5380_STATS
					collect_stats(hostdata, cmd);
#endif
					cmd->scsi_done(cmd);
					cmd = hostdata->connected;
					break;
#endif /* def LINKED */
				case ABORT:
				case COMMAND_COMPLETE:
					/* Accept message by clearing ACK */
					NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
					/* ++guenther: possible race with Falcon locking */
					falcon_dont_release++;
					hostdata->connected = NULL;
					QU_PRINTK("scsi%d: command for target %d, lun %d "
						  "completed\n", HOSTNO, cmd->device->id, cmd->device->lun);
#ifdef SUPPORT_TAGS
					cmd_free_tag(cmd);
					if (status_byte(cmd->SCp.Status) == QUEUE_FULL) {
						/* Turn a QUEUE FULL status into BUSY, I think the
						 * mid level cannot handle QUEUE FULL :-( (The
						 * command is retried after BUSY). Also update our
						 * queue size to the number of currently issued
						 * commands now.
						 */
						/* ++Andreas: the mid level code knows about
						   QUEUE_FULL now. */
						TAG_ALLOC *ta = &TagAlloc[cmd->device->id][cmd->device->lun];
						TAG_PRINTK("scsi%d: target %d lun %d returned "
							   "QUEUE_FULL after %d commands\n",
							   HOSTNO, cmd->device->id, cmd->device->lun,
							   ta->nr_allocated);
						if (ta->queue_size > ta->nr_allocated)
							ta->nr_allocated = ta->queue_size;
					}
#else
					hostdata->busy[cmd->device->id] &= ~(1 << cmd->device->lun);
#endif
					/* Enable reselect interrupts */
					NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);

					/*
					 * I'm not sure what the correct thing to do here is :
					 *
					 * If the command that just executed is NOT a request
					 * sense, the obvious thing to do is to set the result
					 * code to the values of the stored parameters.
					 *
					 * If it was a REQUEST SENSE command, we need some way to
					 * differentiate between the failure code of the original
					 * and the failure code of the REQUEST sense - the obvious
					 * case is success, where we fall through and leave the
					 * result code unchanged.
					 *
					 * The non-obvious place is where the REQUEST SENSE failed
					 */

					if (cmd->cmnd[0] != REQUEST_SENSE)
						cmd->result = cmd->SCp.Status | (cmd->SCp.Message << 8);
					else if (status_byte(cmd->SCp.Status) != GOOD)
						cmd->result = (cmd->result & 0x00ffff) | (DID_ERROR << 16);

#ifdef AUTOSENSE
					if ((cmd->cmnd[0] == REQUEST_SENSE) &&
						hostdata->ses.cmd_len) {
						scsi_eh_restore_cmnd(cmd, &hostdata->ses);
						hostdata->ses.cmd_len = 0 ;
					}

					if ((cmd->cmnd[0] != REQUEST_SENSE) &&
					    (status_byte(cmd->SCp.Status) == CHECK_CONDITION)) {
						scsi_eh_prep_cmnd(cmd, &hostdata->ses, NULL, 0, ~0);

						ASEN_PRINTK("scsi%d: performing request sense\n", HOSTNO);

						local_irq_save(flags);
						LIST(cmd,hostdata->issue_queue);
						SET_NEXT(cmd, hostdata->issue_queue);
						hostdata->issue_queue = (Scsi_Cmnd *) cmd;
						local_irq_restore(flags);
						QU_PRINTK("scsi%d: REQUEST SENSE added to head of "
							  "issue queue\n", H_NO(cmd));
					} else
#endif /* def AUTOSENSE */
					{
#ifdef NCR5380_STATS
						collect_stats(hostdata, cmd);
#endif
						cmd->scsi_done(cmd);
					}

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

					while ((NCR5380_read(STATUS_REG) & SR_BSY) && !hostdata->connected)
						barrier();

					falcon_dont_release--;
					/* ++roman: For Falcon SCSI, release the lock on the
					 * ST-DMA here if no other commands are waiting on the
					 * disconnected queue.
					 */
					falcon_release_lock_if_possible(hostdata);
					return;
				case MESSAGE_REJECT:
					/* Accept message by clearing ACK */
					NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
					/* Enable reselect interrupts */
					NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
					switch (hostdata->last_message) {
					case HEAD_OF_QUEUE_TAG:
					case ORDERED_QUEUE_TAG:
					case SIMPLE_QUEUE_TAG:
						/* The target obviously doesn't support tagged
						 * queuing, even though it announced this ability in
						 * its INQUIRY data ?!? (maybe only this LUN?) Ok,
						 * clear 'tagged_supported' and lock the LUN, since
						 * the command is treated as untagged further on.
						 */
						cmd->device->tagged_supported = 0;
						hostdata->busy[cmd->device->id] |= (1 << cmd->device->lun);
						cmd->tag = TAG_NONE;
						TAG_PRINTK("scsi%d: target %d lun %d rejected "
							   "QUEUE_TAG message; tagged queuing "
							   "disabled\n",
							   HOSTNO, cmd->device->id, cmd->device->lun);
						break;
					}
					break;
				case DISCONNECT:
					/* Accept message by clearing ACK */
					NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
					local_irq_save(flags);
					cmd->device->disconnect = 1;
					LIST(cmd,hostdata->disconnected_queue);
					SET_NEXT(cmd, hostdata->disconnected_queue);
					hostdata->connected = NULL;
					hostdata->disconnected_queue = cmd;
					local_irq_restore(flags);
					QU_PRINTK("scsi%d: command for target %d lun %d was "
						  "moved from connected to the "
						  "disconnected_queue\n", HOSTNO,
						  cmd->device->id, cmd->device->lun);
					/*
					 * 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);
					/* Wait for bus free to avoid nasty timeouts */
					while ((NCR5380_read(STATUS_REG) & SR_BSY) && !hostdata->connected)
						barrier();
					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);
					/* Enable reselect interrupts */
					NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
					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
					 * byte, since spi_print_msg() wants the whole thing.
					 */
					extended_msg[0] = EXTENDED_MESSAGE;
					/* Accept first byte by clearing ACK */
					NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);

					EXT_PRINTK("scsi%d: receiving extended message\n", HOSTNO);

					len = 2;
					data = extended_msg + 1;
					phase = PHASE_MSGIN;
					NCR5380_transfer_pio(instance, &phase, &len, &data);
					EXT_PRINTK("scsi%d: length=%d, code=0x%02x\n", HOSTNO,
						   (int)extended_msg[1], (int)extended_msg[2]);

					if (!len && extended_msg[1] <=
					    (sizeof(extended_msg) - 1)) {
						/* 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);
						EXT_PRINTK("scsi%d: message received, residual %d\n",
							   HOSTNO, len);

						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(KERN_NOTICE "scsi%d: error receiving "
						       "extended message\n", HOSTNO);
						tmp = 0;
					} else {
						printk(KERN_NOTICE "scsi%d: extended message "
							   "code %02x length %d is too long\n",
							   HOSTNO, extended_msg[2], extended_msg[1]);
						tmp = 0;
					}
					/* Fall through to reject message */

					/*
					 * If we get something weird that we aren't expecting,
					 * reject it.
					 */
				default:
					if (!tmp) {
						printk(KERN_DEBUG "scsi%d: rejecting message ", HOSTNO);
						spi_print_msg(extended_msg);
						printk("\n");
					} else if (tmp != EXTENDED_MESSAGE)
						printk(KERN_DEBUG "scsi%d: rejecting unknown "
						       "message %02x from target %d, lun %d\n",
						       HOSTNO, tmp, cmd->device->id, cmd->device->lun);
					else
						printk(KERN_DEBUG "scsi%d: rejecting unknown "
						       "extended message "
						       "code %02x, length %d from target %d, lun %d\n",
						       HOSTNO, extended_msg[1], extended_msg[0],
						       cmd->device->id, cmd->device->lun);


					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) {
#ifdef SUPPORT_TAGS
					cmd_free_tag(cmd);
#else
					hostdata->busy[cmd->device->id] &= ~(1 << cmd->device->lun);
#endif
					hostdata->connected = NULL;
					cmd->result = DID_ERROR << 16;
#ifdef NCR5380_STATS
					collect_stats(hostdata, cmd);
#endif
					cmd->scsi_done(cmd);
					NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
					falcon_release_lock_if_possible(hostdata);
					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", HOSTNO);
				NCR_PRINT(NDEBUG_ANY);
			} /* switch(phase) */
		} /* if (tmp * SR_REQ) */
	} /* while (1) */
}

/*
 * Function : void NCR5380_reselect (struct Scsi_Host *instance)
 *
 * Purpose : does reselection, initializing the instance->connected
 *	field to point to the Scsi_Cmnd for which the I_T_L or I_T_L_Q
 *	nexus has been reestablished,
 *
 * Inputs : instance - this instance of the NCR5380.
 *
 */


static void NCR5380_reselect(struct Scsi_Host *instance)
{
	SETUP_HOSTDATA(instance);
	unsigned char target_mask;
	unsigned char lun, phase;
	int len;
#ifdef SUPPORT_TAGS
	unsigned char tag;
#endif
	unsigned char msg[3];
	unsigned char *data;
	Scsi_Cmnd *tmp = NULL, *prev;
/*	unsigned long flags; */

	/*
	 * Disable arbitration, etc. since the host adapter obviously
	 * lost, and tell an interrupted NCR5380_select() to restart.
	 */

	NCR5380_write(MODE_REG, MR_BASE);
	hostdata->restart_select = 1;

	target_mask = NCR5380_read(CURRENT_SCSI_DATA_REG) & ~(hostdata->id_mask);

	RSL_PRINTK("scsi%d: reselect\n", HOSTNO);

	/*
	 * 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);

	while (NCR5380_read(STATUS_REG) & SR_SEL)
		;
	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);

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

	while (!(NCR5380_read(STATUS_REG) & SR_REQ))
		;

	len = 1;
	data = msg;
	phase = PHASE_MSGIN;
	NCR5380_transfer_pio(instance, &phase, &len, &data);

	if (!(msg[0] & 0x80)) {
		printk(KERN_DEBUG "scsi%d: expecting IDENTIFY message, got ", HOSTNO);
		spi_print_msg(msg);
		do_abort(instance);
		return;
	}
	lun = (msg[0] & 0x07);

#ifdef SUPPORT_TAGS
	/* If the phase is still MSGIN, the target wants to send some more
	 * messages. In case it supports tagged queuing, this is probably a
	 * SIMPLE_QUEUE_TAG for the I_T_L_Q nexus.
	 */
	tag = TAG_NONE;
	if (phase == PHASE_MSGIN && setup_use_tagged_queuing) {
		/* Accept previous IDENTIFY message by clearing ACK */
		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
		len = 2;
		data = msg + 1;
		if (!NCR5380_transfer_pio(instance, &phase, &len, &data) &&
		    msg[1] == SIMPLE_QUEUE_TAG)
			tag = msg[2];
		TAG_PRINTK("scsi%d: target mask %02x, lun %d sent tag %d at "
			   "reselection\n", HOSTNO, target_mask, lun, tag);
	}
#endif

	/*
	 * 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.
	 */

	for (tmp = (Scsi_Cmnd *) hostdata->disconnected_queue, prev = NULL;
	     tmp; prev = tmp, tmp = NEXT(tmp)) {
		if ((target_mask == (1 << tmp->device->id)) && (lun == tmp->device->lun)
#ifdef SUPPORT_TAGS
		    && (tag == tmp->tag)
#endif
		    ) {
			/* ++guenther: prevent race with falcon_release_lock */
			falcon_dont_release++;
			if (prev) {
				REMOVE(prev, NEXT(prev), tmp, NEXT(tmp));
				SET_NEXT(prev, NEXT(tmp));
			} else {
				REMOVE(-1, hostdata->disconnected_queue, tmp, NEXT(tmp));
				hostdata->disconnected_queue = NEXT(tmp);
			}
			SET_NEXT(tmp, NULL);
			break;
		}
	}

	if (!tmp) {
		printk(KERN_WARNING "scsi%d: warning: target bitmask %02x lun %d "
#ifdef SUPPORT_TAGS
		       "tag %d "
#endif
		       "not in disconnected_queue.\n",
		       HOSTNO, target_mask, lun
#ifdef SUPPORT_TAGS
		       , tag
#endif
			);
		/*
		 * Since we have an established nexus that we can't do anything
		 * with, we must abort it.
		 */
		do_abort(instance);
		return;
	}

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

	hostdata->connected = tmp;
	RSL_PRINTK("scsi%d: nexus established, target = %d, lun = %d, tag = %d\n",
		   HOSTNO, tmp->device->id, tmp->device->lun, tmp->tag);
	falcon_dont_release--;
}


/*
 * Function : int NCR5380_abort (Scsi_Cmnd *cmd)