xref: /freebsd/sys/dev/aic7xxx/aic7xxx.seq (revision ee2ea5ceafed78a5bd9810beb9e3ca927180c226)
1/*
2 * Adaptec 274x/284x/294x device driver firmware for Linux and FreeBSD.
3 *
4 * Copyright (c) 1994-2001 Justin T. Gibbs.
5 * Copyright (c) 2000-2001 Adaptec Inc.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions, and the following disclaimer,
13 *    without modification.
14 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
15 *    substantially similar to the "NO WARRANTY" disclaimer below
16 *    ("Disclaimer") and any redistribution must be conditioned upon
17 *    including a substantially similar Disclaimer requirement for further
18 *    binary redistribution.
19 * 3. Neither the names of the above-listed copyright holders nor the names
20 *    of any contributors may be used to endorse or promote products derived
21 *    from this software without specific prior written permission.
22 *
23 * Alternatively, this software may be distributed under the terms of the
24 * GNU General Public License ("GPL") version 2 as published by the Free
25 * Software Foundation.
26 *
27 * NO WARRANTY
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
36 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
37 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
38 * POSSIBILITY OF SUCH DAMAGES.
39 *
40 * $FreeBSD$
41 */
42
43VERSION = "$Id: //depot/aic7xxx/aic7xxx/aic7xxx.seq#40 $"
44PATCH_ARG_LIST = "struct ahc_softc *ahc"
45
46#include "aic7xxx.reg"
47#include "scsi_message.h"
48
49/*
50 * A few words on the waiting SCB list:
51 * After starting the selection hardware, we check for reconnecting targets
52 * as well as for our selection to complete just in case the reselection wins
53 * bus arbitration.  The problem with this is that we must keep track of the
54 * SCB that we've already pulled from the QINFIFO and started the selection
55 * on just in case the reselection wins so that we can retry the selection at
56 * a later time.  This problem cannot be resolved by holding a single entry
57 * in scratch ram since a reconnecting target can request sense and this will
58 * create yet another SCB waiting for selection.  The solution used here is to
59 * use byte 27 of the SCB as a psuedo-next pointer and to thread a list
60 * of SCBs that are awaiting selection.  Since 0-0xfe are valid SCB indexes,
61 * SCB_LIST_NULL is 0xff which is out of range.  An entry is also added to
62 * this list everytime a request sense occurs or after completing a non-tagged
63 * command for which a second SCB has been queued.  The sequencer will
64 * automatically consume the entries.
65 */
66
67bus_free_sel:
68	/*
69	 * Turn off the selection hardware.  We need to reset the
70	 * selection request in order to perform a new selection.
71	 */
72	and	SCSISEQ, TEMODE|ENSELI|ENRSELI|ENAUTOATNP, SCSISEQ;
73	and	SIMODE1, ~ENBUSFREE;
74poll_for_work:
75	call	clear_target_state;
76	and	SXFRCTL0, ~SPIOEN;
77	if ((ahc->features & AHC_ULTRA2) != 0) {
78		clr	SCSIBUSL;
79	}
80	test	SCSISEQ, ENSELO	jnz poll_for_selection;
81	if ((ahc->features & AHC_TWIN) != 0) {
82		xor	SBLKCTL,SELBUSB;	/* Toggle to the other bus */
83		test	SCSISEQ, ENSELO		jnz poll_for_selection;
84	}
85	cmp	WAITING_SCBH,SCB_LIST_NULL jne start_waiting;
86poll_for_work_loop:
87	if ((ahc->features & AHC_TWIN) != 0) {
88		xor	SBLKCTL,SELBUSB;	/* Toggle to the other bus */
89	}
90	test	SSTAT0, SELDO|SELDI	jnz selection;
91test_queue:
92	/* Has the driver posted any work for us? */
93BEGIN_CRITICAL;
94	if ((ahc->features & AHC_QUEUE_REGS) != 0) {
95		test	QOFF_CTLSTA, SCB_AVAIL jz poll_for_work_loop;
96	} else {
97		mov	A, QINPOS;
98		cmp	KERNEL_QINPOS, A je poll_for_work_loop;
99	}
100	mov	ARG_1, NEXT_QUEUED_SCB;
101
102	/*
103	 * We have at least one queued SCB now and we don't have any
104	 * SCBs in the list of SCBs awaiting selection.  Allocate a
105	 * card SCB for the host's SCB and get to work on it.
106	 */
107	if ((ahc->flags & AHC_PAGESCBS) != 0) {
108		mov	ALLZEROS	call	get_free_or_disc_scb;
109	} else {
110		/* In the non-paging case, the SCBID == hardware SCB index */
111		mov	SCBPTR, ARG_1;
112	}
113	or	SEQ_FLAGS2, SCB_DMA;
114END_CRITICAL;
115dma_queued_scb:
116	/*
117	 * DMA the SCB from host ram into the current SCB location.
118	 */
119	mvi	DMAPARAMS, HDMAEN|DIRECTION|FIFORESET;
120	mov	ARG_1	call dma_scb;
121	/*
122	 * Check one last time to see if this SCB was canceled
123	 * before we completed the DMA operation.  If it was,
124	 * the QINFIFO next pointer will not match our saved
125	 * value.
126	 */
127	mov	A, ARG_1;
128BEGIN_CRITICAL;
129	cmp	NEXT_QUEUED_SCB, A jne abort_qinscb;
130	if ((ahc->flags & AHC_SEQUENCER_DEBUG) != 0) {
131		cmp	SCB_TAG, A je . + 2;
132		mvi	SCB_MISMATCH call set_seqint;
133	}
134	mov	NEXT_QUEUED_SCB, SCB_NEXT;
135	mov	SCB_NEXT,WAITING_SCBH;
136	mov	WAITING_SCBH, SCBPTR;
137	if ((ahc->features & AHC_QUEUE_REGS) != 0) {
138		mov	NONE, SNSCB_QOFF;
139	} else {
140		inc	QINPOS;
141	}
142	and	SEQ_FLAGS2, ~SCB_DMA;
143END_CRITICAL;
144start_waiting:
145	/*
146	 * Start the first entry on the waiting SCB list.
147	 */
148	mov	SCBPTR, WAITING_SCBH;
149	call	start_selection;
150
151poll_for_selection:
152	/*
153	 * Twin channel devices cannot handle things like SELTO
154	 * interrupts on the "background" channel.  So, while
155	 * selecting, keep polling the current channel until
156	 * either a selection or reselection occurs.
157	 */
158	test	SSTAT0, SELDO|SELDI	jz poll_for_selection;
159
160selection:
161	/*
162	 * We aren't expecting a bus free, so interrupt
163	 * the kernel driver if it happens.
164	 */
165	mvi	CLRSINT1,CLRBUSFREE;
166	if ((ahc->features & AHC_DT) == 0) {
167		or	SIMODE1, ENBUSFREE;
168	}
169
170	/*
171	 * Guard against a bus free after (re)selection
172	 * but prior to enabling the busfree interrupt.  SELDI
173	 * and SELDO will be cleared in that case.
174	 */
175	test	SSTAT0, SELDI|SELDO	jz bus_free_sel;
176	test	SSTAT0,SELDO	jnz select_out;
177select_in:
178	if ((ahc->flags & AHC_TARGETROLE) != 0) {
179		if ((ahc->flags & AHC_INITIATORROLE) != 0) {
180			test	SSTAT0, TARGET	jz initiator_reselect;
181		}
182		mvi	CLRSINT0, CLRSELDI;
183
184		/*
185		 * We've just been selected.  Assert BSY and
186		 * setup the phase for receiving messages
187		 * from the target.
188		 */
189		mvi	SCSISIGO, P_MESGOUT|BSYO;
190
191		/*
192		 * Setup the DMA for sending the identify and
193		 * command information.
194		 */
195		or	SEQ_FLAGS, CMDPHASE_PENDING;
196
197		mov     A, TQINPOS;
198		if ((ahc->features & AHC_CMD_CHAN) != 0) {
199			mvi	DINDEX, CCHADDR;
200			mvi	SHARED_DATA_ADDR call set_32byte_addr;
201			mvi	CCSCBCTL, CCSCBRESET;
202		} else {
203			mvi	DINDEX, HADDR;
204			mvi	SHARED_DATA_ADDR call set_32byte_addr;
205			mvi	DFCNTRL, FIFORESET;
206		}
207
208		/* Initiator that selected us */
209		and	SAVED_SCSIID, SELID_MASK, SELID;
210		/* The Target ID we were selected at */
211		if ((ahc->features & AHC_MULTI_TID) != 0) {
212			and	A, OID, TARGIDIN;
213		} else if ((ahc->features & AHC_ULTRA2) != 0) {
214			and	A, OID, SCSIID_ULTRA2;
215		} else {
216			and	A, OID, SCSIID;
217		}
218		or	SAVED_SCSIID, A;
219		if ((ahc->features & AHC_TWIN) != 0) {
220			test 	SBLKCTL, SELBUSB jz . + 2;
221			or	SAVED_SCSIID, TWIN_CHNLB;
222		}
223		if ((ahc->features & AHC_CMD_CHAN) != 0) {
224			mov	CCSCBRAM, SAVED_SCSIID;
225		} else {
226			mov	DFDAT, SAVED_SCSIID;
227		}
228
229		/*
230		 * If ATN isn't asserted, the target isn't interested
231		 * in talking to us.  Go directly to bus free.
232		 * XXX SCSI-1 may require us to assume lun 0 if
233		 * ATN is false.
234		 */
235		test	SCSISIGI, ATNI	jz	target_busfree;
236
237		/*
238		 * Watch ATN closely now as we pull in messages from the
239		 * initiator.  We follow the guidlines from section 6.5
240		 * of the SCSI-2 spec for what messages are allowed when.
241		 */
242		call	target_inb;
243
244		/*
245		 * Our first message must be one of IDENTIFY, ABORT, or
246		 * BUS_DEVICE_RESET.
247		 */
248		test	DINDEX, MSG_IDENTIFYFLAG jz host_target_message_loop;
249		/* Store for host */
250		if ((ahc->features & AHC_CMD_CHAN) != 0) {
251			mov	CCSCBRAM, DINDEX;
252		} else {
253			mov	DFDAT, DINDEX;
254		}
255		and	SAVED_LUN, MSG_IDENTIFY_LUNMASK, DINDEX;
256
257		/* Remember for disconnection decision */
258		test	DINDEX, MSG_IDENTIFY_DISCFLAG jnz . + 2;
259		/* XXX Honor per target settings too */
260		or	SEQ_FLAGS, NO_DISCONNECT;
261
262		test	SCSISIGI, ATNI	jz	ident_messages_done;
263		call	target_inb;
264		/*
265		 * If this is a tagged request, the tagged message must
266		 * immediately follow the identify.  We test for a valid
267		 * tag message by seeing if it is >= MSG_SIMPLE_Q_TAG and
268		 * < MSG_IGN_WIDE_RESIDUE.
269		 */
270		add	A, -MSG_SIMPLE_Q_TAG, DINDEX;
271		jnc	ident_messages_done_msg_pending;
272		add	A, -MSG_IGN_WIDE_RESIDUE, DINDEX;
273		jc	ident_messages_done_msg_pending;
274
275		/* Store for host */
276		if ((ahc->features & AHC_CMD_CHAN) != 0) {
277			mov	CCSCBRAM, DINDEX;
278		} else {
279			mov	DFDAT, DINDEX;
280		}
281
282		/*
283		 * If the initiator doesn't feel like providing a tag number,
284		 * we've got a failed selection and must transition to bus
285		 * free.
286		 */
287		test	SCSISIGI, ATNI	jz	target_busfree;
288
289		/*
290		 * Store the tag for the host.
291		 */
292		call	target_inb;
293		if ((ahc->features & AHC_CMD_CHAN) != 0) {
294			mov	CCSCBRAM, DINDEX;
295		} else {
296			mov	DFDAT, DINDEX;
297		}
298		mov	INITIATOR_TAG, DINDEX;
299		or	SEQ_FLAGS, TARGET_CMD_IS_TAGGED;
300
301ident_messages_done:
302		/* Terminate the ident list */
303		if ((ahc->features & AHC_CMD_CHAN) != 0) {
304			mvi	CCSCBRAM, SCB_LIST_NULL;
305		} else {
306			mvi	DFDAT, SCB_LIST_NULL;
307		}
308		or	SEQ_FLAGS, TARG_CMD_PENDING|IDENTIFY_SEEN;
309		test	SEQ_FLAGS2, TARGET_MSG_PENDING
310			jnz target_mesgout_pending;
311		test	SCSISIGI, ATNI jnz target_mesgout_continue;
312		jmp	target_ITloop;
313
314
315ident_messages_done_msg_pending:
316		or	SEQ_FLAGS2, TARGET_MSG_PENDING;
317		jmp	ident_messages_done;
318
319		/*
320		 * Pushed message loop to allow the kernel to
321		 * run it's own target mode message state engine.
322		 */
323host_target_message_loop:
324		mvi	HOST_MSG_LOOP call set_seqint;
325		cmp	RETURN_1, EXIT_MSG_LOOP	je target_ITloop;
326		test	SSTAT0, SPIORDY jz .;
327		jmp	host_target_message_loop;
328	}
329
330if ((ahc->flags & AHC_INITIATORROLE) != 0) {
331/*
332 * Reselection has been initiated by a target. Make a note that we've been
333 * reselected, but haven't seen an IDENTIFY message from the target yet.
334 */
335initiator_reselect:
336	/* XXX test for and handle ONE BIT condition */
337	or	SXFRCTL0, SPIOEN|CLRSTCNT|CLRCHN;
338	and	SAVED_SCSIID, SELID_MASK, SELID;
339	if ((ahc->features & AHC_ULTRA2) != 0) {
340		and	A, OID, SCSIID_ULTRA2;
341	} else {
342		and	A, OID, SCSIID;
343	}
344	or	SAVED_SCSIID, A;
345	if ((ahc->features & AHC_TWIN) != 0) {
346		test	SBLKCTL, SELBUSB	jz . + 2;
347		or	SAVED_SCSIID, TWIN_CHNLB;
348	}
349	mvi	CLRSINT0, CLRSELDI;
350	jmp	ITloop;
351}
352
353abort_qinscb:
354	call	add_scb_to_free_list;
355	jmp	poll_for_work_loop;
356
357start_selection:
358	/*
359	 * If bus reset interrupts have been disabled (from a previous
360	 * reset), re-enable them now.  Resets are only of interest
361	 * when we have outstanding transactions, so we can safely
362	 * defer re-enabling the interrupt until, as an initiator,
363	 * we start sending out transactions again.
364	 */
365	test	SIMODE1, ENSCSIRST	jnz . + 3;
366	mvi	CLRSINT1, CLRSCSIRSTI;
367	or	SIMODE1, ENSCSIRST;
368	if ((ahc->features & AHC_TWIN) != 0) {
369		and	SINDEX,~SELBUSB,SBLKCTL;/* Clear channel select bit */
370		test	SCB_SCSIID, TWIN_CHNLB jz . + 2;
371		or	SINDEX, SELBUSB;
372		mov	SBLKCTL,SINDEX;		/* select channel */
373	}
374initialize_scsiid:
375	if ((ahc->features & AHC_ULTRA2) != 0) {
376		mov	SCSIID_ULTRA2, SCB_SCSIID;
377	} else if ((ahc->features & AHC_TWIN) != 0) {
378		and	SCSIID, TWIN_TID|OID, SCB_SCSIID;
379	} else {
380		mov	SCSIID, SCB_SCSIID;
381	}
382	if ((ahc->flags & AHC_TARGETROLE) != 0) {
383		mov	SINDEX, SCSISEQ_TEMPLATE;
384		test	SCB_CONTROL, TARGET_SCB jz . + 2;
385		or	SINDEX, TEMODE;
386		mov	SCSISEQ, SINDEX ret;
387	} else {
388		mov	SCSISEQ, SCSISEQ_TEMPLATE ret;
389	}
390
391/*
392 * Initialize transfer settings and clear the SCSI channel.
393 * SINDEX should contain any additional bit's the client wants
394 * set in SXFRCTL0.  We also assume that the current SCB is
395 * a valid SCB for the target we wish to talk to.
396 */
397initialize_channel:
398	or	SXFRCTL0, SPIOEN|CLRSTCNT|CLRCHN;
399set_transfer_settings:
400	if ((ahc->features & AHC_ULTRA) != 0) {
401		test	SCB_CONTROL, ULTRAENB jz . + 2;
402		or	SXFRCTL0, FAST20;
403	}
404	/*
405	 * Initialize SCSIRATE with the appropriate value for this target.
406	 */
407	if ((ahc->features & AHC_ULTRA2) != 0) {
408		bmov	SCSIRATE, SCB_SCSIRATE, 2 ret;
409	} else {
410		mov	SCSIRATE, SCB_SCSIRATE ret;
411	}
412
413if ((ahc->flags & AHC_TARGETROLE) != 0) {
414/*
415 * We carefully toggle SPIOEN to allow us to return the
416 * message byte we receive so it can be checked prior to
417 * driving REQ on the bus for the next byte.
418 */
419target_inb:
420	/*
421	 * Drive REQ on the bus by enabling SCSI PIO.
422	 */
423	or	SXFRCTL0, SPIOEN;
424	/* Wait for the byte */
425	test	SSTAT0, SPIORDY jz .;
426	/* Prevent our read from triggering another REQ */
427	and	SXFRCTL0, ~SPIOEN;
428	/* Save latched contents */
429	mov	DINDEX, SCSIDATL ret;
430}
431
432/*
433 * After the selection, remove this SCB from the "waiting SCB"
434 * list.  This is achieved by simply moving our "next" pointer into
435 * WAITING_SCBH.  Our next pointer will be set to null the next time this
436 * SCB is used, so don't bother with it now.
437 */
438select_out:
439	/* Turn off the selection hardware */
440	and	SCSISEQ, TEMODE|ENSELI|ENRSELI|ENAUTOATNP, SCSISEQ;
441	mvi	CLRSINT0, CLRSELDO;
442	mov	SCBPTR, WAITING_SCBH;
443	mov	WAITING_SCBH,SCB_NEXT;
444	mov	SAVED_SCSIID, SCB_SCSIID;
445	mov	SAVED_LUN, SCB_LUN;
446	call	initialize_channel;
447	if ((ahc->flags & AHC_TARGETROLE) != 0) {
448		test	SSTAT0, TARGET	jz initiator_select;
449
450		/*
451		 * We've just re-selected an initiator.
452		 * Assert BSY and setup the phase for
453		 * sending our identify messages.
454		 */
455		mvi	P_MESGIN|BSYO call change_phase;
456
457		/*
458		 * Start out with a simple identify message.
459		 */
460		or	SCB_LUN, MSG_IDENTIFYFLAG call target_outb;
461
462		/*
463		 * If we are the result of a tagged command, send
464		 * a simple Q tag and the tag id.
465		 */
466		test	SCB_CONTROL, TAG_ENB	jz . + 3;
467		mvi	MSG_SIMPLE_Q_TAG call target_outb;
468		mov	SCB_TARGET_ITAG call target_outb;
469target_synccmd:
470		/*
471		 * Now determine what phases the host wants us
472		 * to go through.
473		 */
474		mov	SEQ_FLAGS, SCB_TARGET_PHASES;
475
476		test	SCB_CONTROL, MK_MESSAGE	jz target_ITloop;
477		mvi	P_MESGIN|BSYO call change_phase;
478		jmp	host_target_message_loop;
479target_ITloop:
480		/*
481		 * Start honoring ATN signals now that
482		 * we properly identified ourselves.
483		 */
484		test	SCSISIGI, ATNI			jnz target_mesgout;
485		test	SEQ_FLAGS, CMDPHASE_PENDING	jnz target_cmdphase;
486		test	SEQ_FLAGS, DPHASE_PENDING	jnz target_dphase;
487		test	SEQ_FLAGS, SPHASE_PENDING	jnz target_sphase;
488
489		/*
490		 * No more work to do.  Either disconnect or not depending
491		 * on the state of NO_DISCONNECT.
492		 */
493		test	SEQ_FLAGS, NO_DISCONNECT jz target_disconnect;
494		mov	RETURN_1, ALLZEROS;
495		call	complete_target_cmd;
496		cmp	RETURN_1, CONT_MSG_LOOP jne .;
497		if ((ahc->flags & AHC_PAGESCBS) != 0) {
498			mov	ALLZEROS	call	get_free_or_disc_scb;
499		}
500		mvi	DMAPARAMS, HDMAEN|DIRECTION|FIFORESET;
501		mov	SCB_TAG	 call dma_scb;
502		call	set_transfer_settings;
503		jmp	target_synccmd;
504
505target_mesgout:
506		mvi	SCSISIGO, P_MESGOUT|BSYO;
507target_mesgout_continue:
508		call	target_inb;
509target_mesgout_pending:
510		/* Local Processing goes here... */
511		jmp	host_target_message_loop;
512
513target_disconnect:
514		mvi	P_MESGIN|BSYO call change_phase;
515		test	SEQ_FLAGS, DPHASE	jz . + 2;
516		mvi	MSG_SAVEDATAPOINTER call target_outb;
517		mvi	MSG_DISCONNECT call target_outb;
518
519target_busfree_wait:
520		/* Wait for preceding I/O session to complete. */
521		test	SCSISIGI, ACKI jnz .;
522target_busfree:
523		and	SIMODE1, ~ENBUSFREE;
524		if ((ahc->features & AHC_ULTRA2) != 0) {
525			clr	SCSIBUSL;
526		}
527		clr	SCSISIGO;
528		mvi	LASTPHASE, P_BUSFREE;
529		call	complete_target_cmd;
530		jmp	poll_for_work;
531
532target_cmdphase:
533		/*
534		 * The target has dropped ATN (doesn't want to abort or BDR)
535		 * and we believe this selection to be valid.  If the ring
536		 * buffer for new commands is full, return busy or queue full.
537		 */
538		if ((ahc->features & AHC_HS_MAILBOX) != 0) {
539			and	A, HOST_TQINPOS, HS_MAILBOX;
540		} else {
541			mov	A, KERNEL_TQINPOS;
542		}
543		cmp	TQINPOS, A jne tqinfifo_has_space;
544		mvi	P_STATUS|BSYO call change_phase;
545		test	SEQ_FLAGS, TARGET_CMD_IS_TAGGED jz . + 3;
546		mvi	STATUS_QUEUE_FULL call target_outb;
547		jmp	target_busfree_wait;
548		mvi	STATUS_BUSY call target_outb;
549		jmp	target_busfree_wait;
550tqinfifo_has_space:
551		mvi	P_COMMAND|BSYO call change_phase;
552		call	target_inb;
553		mov	A, DINDEX;
554		/* Store for host */
555		if ((ahc->features & AHC_CMD_CHAN) != 0) {
556			mov	CCSCBRAM, A;
557		} else {
558			mov	DFDAT, A;
559		}
560
561		/*
562		 * Determine the number of bytes to read
563		 * based on the command group code via table lookup.
564		 * We reuse the first 8 bytes of the TARG_SCSIRATE
565		 * BIOS array for this table. Count is one less than
566		 * the total for the command since we've already fetched
567		 * the first byte.
568		 */
569		shr	A, CMD_GROUP_CODE_SHIFT;
570		add	SINDEX, CMDSIZE_TABLE, A;
571		mov	A, SINDIR;
572
573		test	A, 0xFF jz command_phase_done;
574		or	SXFRCTL0, SPIOEN;
575command_loop:
576		test	SSTAT0, SPIORDY jz .;
577		cmp	A, 1 jne . + 2;
578		and	SXFRCTL0, ~SPIOEN;	/* Last Byte */
579		if ((ahc->features & AHC_CMD_CHAN) != 0) {
580			mov	CCSCBRAM, SCSIDATL;
581		} else {
582			mov	DFDAT, SCSIDATL;
583		}
584		dec	A;
585		test	A, 0xFF jnz command_loop;
586
587command_phase_done:
588		and	SEQ_FLAGS, ~CMDPHASE_PENDING;
589		jmp	target_ITloop;
590
591target_dphase:
592		/*
593		 * Data phases on the bus are from the
594		 * perspective of the initiator.  The dma
595		 * code looks at LASTPHASE to determine the
596		 * data direction of the DMA.  Toggle it for
597		 * target transfers.
598		 */
599		xor	LASTPHASE, IOI, SCB_TARGET_DATA_DIR;
600		or	SCB_TARGET_DATA_DIR, BSYO call change_phase;
601		jmp	p_data;
602
603target_sphase:
604		mvi	P_STATUS|BSYO call change_phase;
605		mvi	LASTPHASE, P_STATUS;
606		mov	SCB_SCSI_STATUS call target_outb;
607		/* XXX Watch for ATN or parity errors??? */
608		mvi	SCSISIGO, P_MESGIN|BSYO;
609		/* MSG_CMDCMPLT is 0, but we can't do an immediate of 0 */
610		mov	ALLZEROS call target_outb;
611		jmp	target_busfree_wait;
612
613complete_target_cmd:
614		test	SEQ_FLAGS, TARG_CMD_PENDING	jnz . + 2;
615		mov	SCB_TAG jmp complete_post;
616		if ((ahc->features & AHC_CMD_CHAN) != 0) {
617			/* Set the valid byte */
618			mvi	CCSCBADDR, 24;
619			mov	CCSCBRAM, ALLONES;
620			mvi	CCHCNT, 28;
621			or	CCSCBCTL, CCSCBEN|CCSCBRESET;
622			test	CCSCBCTL, CCSCBDONE jz .;
623			clr	CCSCBCTL;
624		} else {
625			/* Set the valid byte */
626			or	DFCNTRL, FIFORESET;
627			mvi	DFWADDR, 3; /* Third 64bit word or byte 24 */
628			mov	DFDAT, ALLONES;
629			mvi	28	call set_hcnt;
630			or	DFCNTRL, HDMAEN|FIFOFLUSH;
631			call	dma_finish;
632		}
633		inc	TQINPOS;
634		mvi	INTSTAT,CMDCMPLT ret;
635	}
636
637if ((ahc->flags & AHC_INITIATORROLE) != 0) {
638initiator_select:
639	/*
640	 * As soon as we get a successful selection, the target
641	 * should go into the message out phase since we have ATN
642	 * asserted.
643	 */
644	mvi	MSG_OUT, MSG_IDENTIFYFLAG;
645	or	SEQ_FLAGS, IDENTIFY_SEEN;
646
647	/*
648	 * Main loop for information transfer phases.  Wait for the
649	 * target to assert REQ before checking MSG, C/D and I/O for
650	 * the bus phase.
651	 */
652mesgin_phasemis:
653ITloop:
654	call	phase_lock;
655
656	mov	A, LASTPHASE;
657
658	test	A, ~P_DATAIN	jz p_data;
659	cmp	A,P_COMMAND	je p_command;
660	cmp	A,P_MESGOUT	je p_mesgout;
661	cmp	A,P_STATUS	je p_status;
662	cmp	A,P_MESGIN	je p_mesgin;
663
664	mvi	BAD_PHASE call set_seqint;
665	jmp	ITloop;			/* Try reading the bus again. */
666
667await_busfree:
668	and	SIMODE1, ~ENBUSFREE;
669	mov	NONE, SCSIDATL;		/* Ack the last byte */
670	if ((ahc->features & AHC_ULTRA2) != 0) {
671		clr	SCSIBUSL;	/* Prevent bit leakage durint SELTO */
672	}
673	and	SXFRCTL0, ~SPIOEN;
674	test	SSTAT1,REQINIT|BUSFREE	jz .;
675	test	SSTAT1, BUSFREE jnz poll_for_work;
676	mvi	MISSED_BUSFREE call set_seqint;
677}
678
679clear_target_state:
680	/*
681	 * We assume that the kernel driver may reset us
682	 * at any time, even in the middle of a DMA, so
683	 * clear DFCNTRL too.
684	 */
685	clr	DFCNTRL;
686	or	SXFRCTL0, CLRSTCNT|CLRCHN;
687
688	/*
689	 * We don't know the target we will connect to,
690	 * so default to narrow transfers to avoid
691	 * parity problems.
692	 */
693	if ((ahc->features & AHC_ULTRA2) != 0) {
694		bmov	SCSIRATE, ALLZEROS, 2;
695	} else {
696		clr	SCSIRATE;
697		if ((ahc->features & AHC_ULTRA) != 0) {
698			and	SXFRCTL0, ~(FAST20);
699		}
700	}
701	mvi	LASTPHASE, P_BUSFREE;
702	/* clear target specific flags */
703	clr	SEQ_FLAGS ret;
704
705sg_advance:
706	clr	A;			/* add sizeof(struct scatter) */
707	add	SCB_RESIDUAL_SGPTR[0],SG_SIZEOF;
708	adc	SCB_RESIDUAL_SGPTR[1],A;
709	adc	SCB_RESIDUAL_SGPTR[2],A;
710	adc	SCB_RESIDUAL_SGPTR[3],A ret;
711
712if ((ahc->features & AHC_CMD_CHAN) != 0) {
713disable_ccsgen:
714	test	CCSGCTL, CCSGEN jz return;
715	test	CCSGCTL, CCSGDONE jz .;
716disable_ccsgen_fetch_done:
717	clr	CCSGCTL;
718	test	CCSGCTL, CCSGEN jnz .;
719	ret;
720idle_loop:
721	/*
722	 * Do we need any more segments for this transfer?
723	 */
724	test	SCB_RESIDUAL_DATACNT[3], SG_LAST_SEG jnz return;
725
726	/* Did we just finish fetching segs? */
727	cmp	CCSGCTL, CCSGEN|CCSGDONE je idle_sgfetch_complete;
728
729	/* Are we actively fetching segments? */
730	test	CCSGCTL, CCSGEN jnz return;
731
732	/*
733	 * Do we have any prefetch left???
734	 */
735	cmp	CCSGADDR, SG_PREFETCH_CNT jne idle_sg_avail;
736
737	/*
738	 * Need to fetch segments, but we can only do that
739	 * if the command channel is completely idle.  Make
740	 * sure we don't have an SCB prefetch going on.
741	 */
742	test	CCSCBCTL, CCSCBEN jnz return;
743
744	/*
745	 * We fetch a "cacheline aligned" and sized amount of data
746	 * so we don't end up referencing a non-existant page.
747	 * Cacheline aligned is in quotes because the kernel will
748	 * set the prefetch amount to a reasonable level if the
749	 * cacheline size is unknown.
750	 */
751	mvi	CCHCNT, SG_PREFETCH_CNT;
752	and	CCHADDR[0], SG_PREFETCH_ALIGN_MASK, SCB_RESIDUAL_SGPTR;
753	bmov	CCHADDR[1], SCB_RESIDUAL_SGPTR[1], 3;
754	mvi	CCSGCTL, CCSGEN|CCSGRESET ret;
755idle_sgfetch_complete:
756	call	disable_ccsgen_fetch_done;
757	and	CCSGADDR, SG_PREFETCH_ADDR_MASK, SCB_RESIDUAL_SGPTR;
758idle_sg_avail:
759	if ((ahc->features & AHC_ULTRA2) != 0) {
760		/* Does the hardware have space for another SG entry? */
761		test	DFSTATUS, PRELOAD_AVAIL jz return;
762		bmov 	HADDR, CCSGRAM, 7;
763		test	HCNT[0], 0x1 jz . + 2;
764		xor	DATA_COUNT_ODD, 0x1;
765		bmov	SCB_RESIDUAL_DATACNT[3], CCSGRAM, 1;
766		if ((ahc->flags & AHC_39BIT_ADDRESSING) != 0) {
767			mov	SCB_RESIDUAL_DATACNT[3] call set_hhaddr;
768		}
769		call	sg_advance;
770		mov	SINDEX, SCB_RESIDUAL_SGPTR[0];
771		test	DATA_COUNT_ODD, 0x1 jz . + 2;
772		or	SINDEX, ODD_SEG;
773		test	SCB_RESIDUAL_DATACNT[3], SG_LAST_SEG jz . + 2;
774		or	SINDEX, LAST_SEG;
775		mov	SG_CACHE_PRE, SINDEX;
776		/* Load the segment */
777		or	DFCNTRL, PRELOADEN;
778	}
779	ret;
780}
781
782if ((ahc->bugs & AHC_PCI_MWI_BUG) != 0 && ahc->pci_cachesize != 0) {
783/*
784 * Calculate the trailing portion of this S/G segment that cannot
785 * be transferred using memory write and invalidate PCI transactions.
786 * XXX Can we optimize this for PCI writes only???
787 */
788calc_mwi_residual:
789	/*
790	 * If the ending address is on a cacheline boundary,
791	 * there is no need for an extra segment.
792	 */
793	mov	A, HCNT[0];
794	add	A, A, HADDR[0];
795	and	A, CACHESIZE_MASK;
796	test	A, 0xFF jz return;
797
798	/*
799	 * If the transfer is less than a cachline,
800	 * there is no need for an extra segment.
801	 */
802	test	HCNT[1], 0xFF	jnz calc_mwi_residual_final;
803	test	HCNT[2], 0xFF	jnz calc_mwi_residual_final;
804	add	NONE, INVERTED_CACHESIZE_MASK, HCNT[0];
805	jnc	return;
806
807calc_mwi_residual_final:
808	mov	MWI_RESIDUAL, A;
809	not	A;
810	inc	A;
811	add	HCNT[0], A;
812	adc	HCNT[1], -1;
813	adc	HCNT[2], -1 ret;
814}
815
816p_data:
817	test	SEQ_FLAGS,IDENTIFY_SEEN	jnz p_data_okay;
818	mvi	NO_IDENT jmp set_seqint;
819p_data_okay:
820	if ((ahc->features & AHC_ULTRA2) != 0) {
821		mvi	DMAPARAMS, PRELOADEN|SCSIEN|HDMAEN;
822	} else {
823		mvi	DMAPARAMS, WIDEODD|SCSIEN|SDMAEN|HDMAEN|FIFORESET;
824	}
825	test	LASTPHASE, IOI jnz . + 2;
826	or	DMAPARAMS, DIRECTION;
827	if ((ahc->features & AHC_CMD_CHAN) != 0) {
828		/* We don't have any valid S/G elements */
829		mvi	CCSGADDR, SG_PREFETCH_CNT;
830	}
831	test	SEQ_FLAGS, DPHASE	jz data_phase_initialize;
832
833	/*
834	 * If we re-enter the data phase after going through another
835	 * phase, our transfer location has almost certainly been
836	 * corrupted by the interveining, non-data, transfers.  Ask
837	 * the host driver to fix us up based on the transfer residual.
838	 */
839	mvi	PDATA_REINIT	call set_seqint;
840	jmp	data_phase_loop;
841
842data_phase_initialize:
843	/* We have seen a data phase for the first time */
844	or	SEQ_FLAGS, DPHASE;
845
846	/*
847	 * Initialize the DMA address and counter from the SCB.
848	 * Also set SCB_RESIDUAL_SGPTR, including the LAST_SEG
849	 * flag in the highest byte of the data count.  We cannot
850	 * modify the saved values in the SCB until we see a save
851	 * data pointers message.
852	 */
853	if ((ahc->flags & AHC_39BIT_ADDRESSING) != 0) {
854		/* The lowest address byte must be loaded last. */
855		mov	SCB_DATACNT[3] call set_hhaddr;
856	}
857	if ((ahc->features & AHC_CMD_CHAN) != 0) {
858		bmov	HADDR, SCB_DATAPTR, 7;
859		bmov	SCB_RESIDUAL_DATACNT[3], SCB_DATACNT[3], 5;
860	} else {
861		mvi	DINDEX, HADDR;
862		mvi	SCB_DATAPTR	call bcopy_7;
863		mvi	DINDEX, SCB_RESIDUAL_DATACNT + 3;
864		mvi	SCB_DATACNT + 3 call bcopy_5;
865	}
866	if ((ahc->bugs & AHC_PCI_MWI_BUG) != 0 && ahc->pci_cachesize != 0) {
867		call	calc_mwi_residual;
868	}
869	and	SCB_RESIDUAL_SGPTR[0], ~SG_FULL_RESID;
870	and	DATA_COUNT_ODD, 0x1, HCNT[0];
871
872	if ((ahc->features & AHC_ULTRA2) == 0) {
873		if ((ahc->features & AHC_CMD_CHAN) != 0) {
874			bmov	STCNT, HCNT, 3;
875		} else {
876			call	set_stcnt_from_hcnt;
877		}
878	}
879
880data_phase_loop:
881	/* Guard against overruns */
882	test	SCB_RESIDUAL_SGPTR[0], SG_LIST_NULL jz data_phase_inbounds;
883
884	/*
885	 * Turn on `Bit Bucket' mode, wait until the target takes
886	 * us to another phase, and then notify the host.
887	 */
888	and	DMAPARAMS, DIRECTION;
889	mov	DFCNTRL, DMAPARAMS;
890	or	SXFRCTL1,BITBUCKET;
891	if ((ahc->features & AHC_DT) == 0) {
892		test	SSTAT1,PHASEMIS	jz .;
893	} else {
894		test	SCSIPHASE, DATA_PHASE_MASK jnz .;
895	}
896	and	SXFRCTL1, ~BITBUCKET;
897	mvi	DATA_OVERRUN call set_seqint;
898	jmp	ITloop;
899
900data_phase_inbounds:
901	if ((ahc->features & AHC_ULTRA2) != 0) {
902		mov	SINDEX, SCB_RESIDUAL_SGPTR[0];
903		test	SCB_RESIDUAL_DATACNT[3], SG_LAST_SEG jz . + 2;
904		or	SINDEX, LAST_SEG;
905		test	DATA_COUNT_ODD, 0x1 jz . + 2;
906		or	SINDEX, ODD_SEG;
907		mov	SG_CACHE_PRE, SINDEX;
908		mov	DFCNTRL, DMAPARAMS;
909ultra2_dma_loop:
910		call	idle_loop;
911		/*
912		 * The transfer is complete if either the last segment
913		 * completes or the target changes phase.
914		 */
915		test	SG_CACHE_SHADOW, LAST_SEG_DONE jnz ultra2_dmafinish;
916		if ((ahc->features & AHC_DT) == 0) {
917			if ((ahc->flags & AHC_TARGETROLE) != 0) {
918				 /*
919				  * As a target, we control the phases,
920				  * so ignore PHASEMIS.
921				  */
922				test	SSTAT0, TARGET jnz ultra2_dma_loop;
923			}
924			if ((ahc->flags & AHC_INITIATORROLE) != 0) {
925				test	SSTAT1,PHASEMIS	jz ultra2_dma_loop;
926			}
927		} else {
928			test	DFCNTRL, SCSIEN jnz ultra2_dma_loop;
929		}
930
931ultra2_dmafinish:
932		/*
933		 * The transfer has terminated either due to a phase
934		 * change, and/or the completion of the last segment.
935		 * We have two goals here.  Do as much other work
936		 * as possible while the data fifo drains on a read
937		 * and respond as quickly as possible to the standard
938		 * messages (save data pointers/disconnect and command
939		 * complete) that usually follow a data phase.
940		 */
941		if ((ahc->bugs & AHC_AUTOFLUSH_BUG) != 0) {
942			/*
943			 * On chips with broken auto-flush, start
944			 * the flushing process now.  We'll poke
945			 * the chip from time to time to keep the
946			 * flush process going as we complete the
947			 * data phase.
948			 */
949			or	DFCNTRL, FIFOFLUSH;
950		}
951		/*
952		 * We assume that, even though data may still be
953		 * transferring to the host, that the SCSI side of
954		 * the DMA engine is now in a static state.  This
955		 * allows us to update our notion of where we are
956		 * in this transfer.
957		 *
958		 * If, by chance, we stopped before being able
959		 * to fetch additional segments for this transfer,
960		 * yet the last S/G was completely exhausted,
961		 * call our idle loop until it is able to load
962		 * another segment.  This will allow us to immediately
963		 * pickup on the next segment on the next data phase.
964		 *
965		 * If we happened to stop on the last segment, then
966		 * our residual information is still correct from
967		 * the idle loop and there is no need to perform
968		 * any fixups.
969		 */
970ultra2_ensure_sg:
971		test	SG_CACHE_SHADOW, LAST_SEG jz ultra2_shvalid;
972		/* Record if we've consumed all S/G entries */
973		test	SSTAT2, SHVALID	jnz residuals_correct;
974		or	SCB_RESIDUAL_SGPTR[0], SG_LIST_NULL;
975		jmp	residuals_correct;
976
977ultra2_shvalid:
978		test	SSTAT2, SHVALID	jnz sgptr_fixup;
979		call	idle_loop;
980		jmp	ultra2_ensure_sg;
981
982sgptr_fixup:
983		/*
984		 * Fixup the residual next S/G pointer.  The S/G preload
985		 * feature of the chip allows us to load two elements
986		 * in addition to the currently active element.  We
987		 * store the bottom byte of the next S/G pointer in
988		 * the SG_CACEPTR register so we can restore the
989		 * correct value when the DMA completes.  If the next
990		 * sg ptr value has advanced to the point where higher
991		 * bytes in the address have been affected, fix them
992		 * too.
993		 */
994		test	SG_CACHE_SHADOW, 0x80 jz sgptr_fixup_done;
995		test	SCB_RESIDUAL_SGPTR[0], 0x80 jnz sgptr_fixup_done;
996		add	SCB_RESIDUAL_SGPTR[1], -1;
997		adc	SCB_RESIDUAL_SGPTR[2], -1;
998		adc	SCB_RESIDUAL_SGPTR[3], -1;
999sgptr_fixup_done:
1000		and	SCB_RESIDUAL_SGPTR[0], SG_ADDR_MASK, SG_CACHE_SHADOW;
1001		clr	DATA_COUNT_ODD;
1002		test	SG_CACHE_SHADOW, ODD_SEG jz . + 2;
1003		or	DATA_COUNT_ODD, 0x1;
1004		clr	SCB_RESIDUAL_DATACNT[3]; /* We are not the last seg */
1005residuals_correct:
1006		/*
1007		 * Go ahead and shut down the DMA engine now.
1008		 * In the future, we'll want to handle end of
1009		 * transfer messages prior to doing this, but this
1010		 * requires similar restructuring for pre-ULTRA2
1011		 * controllers.
1012		 */
1013		test	DMAPARAMS, DIRECTION jnz ultra2_fifoempty;
1014ultra2_fifoflush:
1015		if ((ahc->features & AHC_DT) == 0) {
1016			if ((ahc->bugs & AHC_AUTOFLUSH_BUG) != 0) {
1017				/*
1018				 * On Rev A of the aic7890, the autoflush
1019				 * feature doesn't function correctly.
1020				 * Perform an explicit manual flush.  During
1021				 * a manual flush, the FIFOEMP bit becomes
1022				 * true every time the PCI FIFO empties
1023				 * regardless of the state of the SCSI FIFO.
1024				 * It can take up to 4 clock cycles for the
1025				 * SCSI FIFO to get data into the PCI FIFO
1026				 * and for FIFOEMP to de-assert.  Here we
1027				 * guard against this condition by making
1028				 * sure the FIFOEMP bit stays on for 5 full
1029				 * clock cycles.
1030				 */
1031				or	DFCNTRL, FIFOFLUSH;
1032				test	DFSTATUS, FIFOEMP jz ultra2_fifoflush;
1033				test	DFSTATUS, FIFOEMP jz ultra2_fifoflush;
1034				test	DFSTATUS, FIFOEMP jz ultra2_fifoflush;
1035				test	DFSTATUS, FIFOEMP jz ultra2_fifoflush;
1036			}
1037			test	DFSTATUS, FIFOEMP jz ultra2_fifoflush;
1038		} else {
1039			/*
1040			 * We enable the auto-ack feature on DT capable
1041			 * controllers.  This means that the controller may
1042			 * have already transferred some overrun bytes into
1043			 * the data FIFO and acked them on the bus.  The only
1044			 * way to detect this situation is to wait for
1045			 * LAST_SEG_DONE to come true on a completed transfer
1046			 * and then test to see if the data FIFO is non-empty.
1047			 */
1048			test	SCB_RESIDUAL_SGPTR[0], SG_LIST_NULL jz . + 4;
1049			test	SG_CACHE_SHADOW, LAST_SEG_DONE jz .;
1050			test	DFSTATUS, FIFOEMP jnz ultra2_fifoempty;
1051			/* Overrun */
1052			jmp	data_phase_loop;
1053			test	DFSTATUS, FIFOEMP jz .;
1054		}
1055ultra2_fifoempty:
1056		/* Don't clobber an inprogress host data transfer */
1057		test	DFSTATUS, MREQPEND	jnz ultra2_fifoempty;
1058ultra2_dmahalt:
1059		and     DFCNTRL, ~(SCSIEN|HDMAEN);
1060		test	DFCNTRL, SCSIEN|HDMAEN jnz .;
1061		if ((ahc->flags & AHC_39BIT_ADDRESSING) != 0) {
1062			/*
1063			 * Keep HHADDR cleared for future, 32bit addressed
1064			 * only, DMA operations.
1065			 *
1066			 * Due to bayonette style S/G handling, our residual
1067			 * data must be "fixed up" once the transfer is halted.
1068			 * Here we fixup the HSHADDR stored in the high byte
1069			 * of the residual data cnt.  By postponing the fixup,
1070			 * we can batch the clearing of HADDR with the fixup.
1071			 * If we halted on the last segment, the residual is
1072			 * already correct.   If we are not on the last
1073			 * segment, copy the high address directly from HSHADDR.
1074			 * We don't need to worry about maintaining the
1075			 * SG_LAST_SEG flag as it will always be false in the
1076			 * case where an update is required.
1077			 */
1078			or	DSCOMMAND1, HADDLDSEL0;
1079			test	SG_CACHE_SHADOW, LAST_SEG jnz . + 2;
1080			mov	SCB_RESIDUAL_DATACNT[3], SHADDR;
1081			clr	HADDR;
1082			and	DSCOMMAND1, ~HADDLDSEL0;
1083		}
1084	} else {
1085		/* If we are the last SG block, tell the hardware. */
1086		if ((ahc->bugs & AHC_PCI_MWI_BUG) != 0
1087		  && ahc->pci_cachesize != 0) {
1088			test	MWI_RESIDUAL, 0xFF jnz dma_mid_sg;
1089		}
1090		test	SCB_RESIDUAL_DATACNT[3], SG_LAST_SEG jz dma_mid_sg;
1091		if ((ahc->flags & AHC_TARGETROLE) != 0) {
1092			test	SSTAT0, TARGET jz dma_last_sg;
1093			if ((ahc->flags & AHC_TMODE_WIDEODD_BUG) != 0) {
1094				test	DMAPARAMS, DIRECTION jz dma_mid_sg;
1095			}
1096		}
1097dma_last_sg:
1098		and	DMAPARAMS, ~WIDEODD;
1099dma_mid_sg:
1100		/* Start DMA data transfer. */
1101		mov	DFCNTRL, DMAPARAMS;
1102dma_loop:
1103		if ((ahc->features & AHC_CMD_CHAN) != 0) {
1104			call	idle_loop;
1105		}
1106		test	SSTAT0,DMADONE	jnz dma_dmadone;
1107		test	SSTAT1,PHASEMIS	jz dma_loop;	/* ie. underrun */
1108dma_phasemis:
1109		/*
1110		 * We will be "done" DMAing when the transfer count goes to
1111		 * zero, or the target changes the phase (in light of this,
1112		 * it makes sense that the DMA circuitry doesn't ACK when
1113		 * PHASEMIS is active).  If we are doing a SCSI->Host transfer,
1114		 * the data FIFO should be flushed auto-magically on STCNT=0
1115		 * or a phase change, so just wait for FIFO empty status.
1116		 */
1117dma_checkfifo:
1118		test	DFCNTRL,DIRECTION	jnz dma_fifoempty;
1119dma_fifoflush:
1120		test	DFSTATUS,FIFOEMP	jz dma_fifoflush;
1121dma_fifoempty:
1122		/* Don't clobber an inprogress host data transfer */
1123		test	DFSTATUS, MREQPEND	jnz dma_fifoempty;
1124
1125		/*
1126		 * Now shut off the DMA and make sure that the DMA
1127		 * hardware has actually stopped.  Touching the DMA
1128		 * counters, etc. while a DMA is active will result
1129		 * in an ILLSADDR exception.
1130		 */
1131dma_dmadone:
1132		and	DFCNTRL, ~(SCSIEN|SDMAEN|HDMAEN);
1133dma_halt:
1134		/*
1135		 * Some revisions of the aic78XX have a problem where, if the
1136		 * data fifo is full, but the PCI input latch is not empty,
1137		 * HDMAEN cannot be cleared.  The fix used here is to drain
1138		 * the prefetched but unused data from the data fifo until
1139		 * there is space for the input latch to drain.
1140		 */
1141		if ((ahc->bugs & AHC_PCI_2_1_RETRY_BUG) != 0) {
1142			mov	NONE, DFDAT;
1143		}
1144		test	DFCNTRL, (SCSIEN|SDMAEN|HDMAEN) jnz dma_halt;
1145
1146		/* See if we have completed this last segment */
1147		test	STCNT[0], 0xff	jnz data_phase_finish;
1148		test	STCNT[1], 0xff	jnz data_phase_finish;
1149		test	STCNT[2], 0xff	jnz data_phase_finish;
1150
1151		/*
1152		 * Advance the scatter-gather pointers if needed
1153		 */
1154		if ((ahc->bugs & AHC_PCI_MWI_BUG) != 0
1155		  && ahc->pci_cachesize != 0) {
1156			test	MWI_RESIDUAL, 0xFF jz no_mwi_resid;
1157			/*
1158			 * Reload HADDR from SHADDR and setup the
1159			 * count to be the size of our residual.
1160			 */
1161			if ((ahc->features & AHC_CMD_CHAN) != 0) {
1162				bmov	HADDR, SHADDR, 4;
1163				mov	HCNT, MWI_RESIDUAL;
1164				bmov	HCNT[1], ALLZEROS, 2;
1165			} else {
1166				mvi	DINDEX, HADDR;
1167				mvi	SHADDR call bcopy_4;
1168				mov	MWI_RESIDUAL call set_hcnt;
1169			}
1170			clr	MWI_RESIDUAL;
1171			jmp	sg_load_done;
1172no_mwi_resid:
1173		}
1174		test	SCB_RESIDUAL_DATACNT[3], SG_LAST_SEG jz sg_load;
1175		or	SCB_RESIDUAL_SGPTR[0], SG_LIST_NULL;
1176		jmp	data_phase_finish;
1177sg_load:
1178		/*
1179		 * Load the next SG element's data address and length
1180		 * into the DMA engine.  If we don't have hardware
1181		 * to perform a prefetch, we'll have to fetch the
1182		 * segment from host memory first.
1183		 */
1184		if ((ahc->features & AHC_CMD_CHAN) != 0) {
1185			/* Wait for the idle loop to complete */
1186			test	CCSGCTL, CCSGEN jz . + 3;
1187			call	idle_loop;
1188			test	CCSGCTL, CCSGEN jnz . - 1;
1189			bmov 	HADDR, CCSGRAM, 7;
1190			/*
1191			 * Workaround for flaky external SCB RAM
1192			 * on certain aic7895 setups.  It seems
1193			 * unable to handle direct transfers from
1194			 * S/G ram to certain SCB locations.
1195			 */
1196			mov	SINDEX, CCSGRAM;
1197			mov	SCB_RESIDUAL_DATACNT[3], SINDEX;
1198		} else {
1199			if ((ahc->flags & AHC_39BIT_ADDRESSING) != 0) {
1200				mov	ALLZEROS call set_hhaddr;
1201			}
1202			mvi	DINDEX, HADDR;
1203			mvi	SCB_RESIDUAL_SGPTR	call bcopy_4;
1204
1205			mvi	SG_SIZEOF	call set_hcnt;
1206
1207			or	DFCNTRL, HDMAEN|DIRECTION|FIFORESET;
1208
1209			call	dma_finish;
1210
1211			mvi	DINDEX, HADDR;
1212			call	dfdat_in_7;
1213			mov	SCB_RESIDUAL_DATACNT[3], DFDAT;
1214		}
1215
1216		if ((ahc->flags & AHC_39BIT_ADDRESSING) != 0) {
1217			mov	SCB_RESIDUAL_DATACNT[3] call set_hhaddr;
1218
1219			/*
1220			 * The lowest address byte must be loaded
1221			 * last as it triggers the computation of
1222			 * some items in the PCI block.  The ULTRA2
1223			 * chips do this on PRELOAD.
1224			 */
1225			mov	HADDR, HADDR;
1226		}
1227		if ((ahc->bugs & AHC_PCI_MWI_BUG) != 0
1228		  && ahc->pci_cachesize != 0) {
1229			call calc_mwi_residual;
1230		}
1231
1232		/* Point to the new next sg in memory */
1233		call	sg_advance;
1234
1235sg_load_done:
1236		if ((ahc->features & AHC_CMD_CHAN) != 0) {
1237			bmov	STCNT, HCNT, 3;
1238		} else {
1239			call	set_stcnt_from_hcnt;
1240		}
1241		/* Track odd'ness */
1242		test	HCNT[0], 0x1 jz . + 2;
1243		xor	DATA_COUNT_ODD, 0x1;
1244
1245		if ((ahc->flags & AHC_TARGETROLE) != 0) {
1246			test	SSTAT0, TARGET jnz data_phase_loop;
1247		}
1248	}
1249data_phase_finish:
1250	/*
1251	 * If the target has left us in data phase, loop through
1252	 * the dma code again.  In the case of ULTRA2 adapters,
1253	 * we should only loop if there is a data overrun.  For
1254	 * all other adapters, we'll loop after each S/G element
1255	 * is loaded as well as if there is an overrun.
1256	 */
1257	if ((ahc->flags & AHC_TARGETROLE) != 0) {
1258		test	SSTAT0, TARGET jnz data_phase_done;
1259	}
1260	if ((ahc->flags & AHC_INITIATORROLE) != 0) {
1261		test	SSTAT1, REQINIT jz .;
1262		if ((ahc->features & AHC_DT) == 0) {
1263			test	SSTAT1,PHASEMIS	jz data_phase_loop;
1264		} else {
1265			test	SCSIPHASE, DATA_PHASE_MASK jnz data_phase_loop;
1266		}
1267	}
1268
1269data_phase_done:
1270	/*
1271	 * After a DMA finishes, save the SG and STCNT residuals back into
1272	 * the SCB.  We use STCNT instead of HCNT, since it's a reflection
1273	 * of how many bytes were transferred on the SCSI (as opposed to the
1274	 * host) bus.
1275	 */
1276	if ((ahc->features & AHC_CMD_CHAN) != 0) {
1277		/* Kill off any pending prefetch */
1278		call	disable_ccsgen;
1279	}
1280
1281	if ((ahc->features & AHC_ULTRA2) == 0) {
1282		/*
1283		 * Clear the high address byte so that all other DMA
1284		 * operations, which use 32bit addressing, can assume
1285		 * HHADDR is 0.
1286		 */
1287		if ((ahc->flags & AHC_39BIT_ADDRESSING) != 0) {
1288			mov	ALLZEROS call set_hhaddr;
1289		}
1290	}
1291
1292	/*
1293	 * Update our residual information before the information is
1294	 * lost by some other type of SCSI I/O (e.g. PIO).  If we have
1295	 * transferred all data, no update is needed.
1296	 *
1297	 */
1298	test	SCB_RESIDUAL_SGPTR, SG_LIST_NULL jnz residual_update_done;
1299	if ((ahc->bugs & AHC_PCI_MWI_BUG) != 0
1300	  && ahc->pci_cachesize != 0) {
1301		if ((ahc->features & AHC_CMD_CHAN) != 0) {
1302			test	MWI_RESIDUAL, 0xFF jz bmov_resid;
1303		}
1304		mov	A, MWI_RESIDUAL;
1305		add	SCB_RESIDUAL_DATACNT[0], A, STCNT[0];
1306		clr	A;
1307		adc	SCB_RESIDUAL_DATACNT[1], A, STCNT[1];
1308		adc	SCB_RESIDUAL_DATACNT[2], A, STCNT[2];
1309		clr	MWI_RESIDUAL;
1310		if ((ahc->features & AHC_CMD_CHAN) != 0) {
1311			jmp	. + 2;
1312bmov_resid:
1313			bmov	SCB_RESIDUAL_DATACNT, STCNT, 3;
1314		}
1315	} else if ((ahc->features & AHC_CMD_CHAN) != 0) {
1316		bmov	SCB_RESIDUAL_DATACNT, STCNT, 3;
1317	} else {
1318		mov	SCB_RESIDUAL_DATACNT[0], STCNT[0];
1319		mov	SCB_RESIDUAL_DATACNT[1], STCNT[1];
1320		mov	SCB_RESIDUAL_DATACNT[2], STCNT[2];
1321	}
1322residual_update_done:
1323	/*
1324	 * Since we've been through a data phase, the SCB_RESID* fields
1325	 * are now initialized.  Clear the full residual flag.
1326	 */
1327	and	SCB_SGPTR[0], ~SG_FULL_RESID;
1328
1329	if ((ahc->features & AHC_ULTRA2) != 0) {
1330		/* Clear the channel in case we return to data phase later */
1331		or	SXFRCTL0, CLRSTCNT|CLRCHN;
1332		or	SXFRCTL0, CLRSTCNT|CLRCHN;
1333	}
1334
1335	if ((ahc->flags & AHC_TARGETROLE) != 0) {
1336		test	SEQ_FLAGS, DPHASE_PENDING jz ITloop;
1337		and	SEQ_FLAGS, ~DPHASE_PENDING;
1338		/*
1339		 * For data-in phases, wait for any pending acks from the
1340		 * initiator before changing phase.  We only need to
1341		 * send Ignore Wide Residue messages for data-in phases.
1342		 */
1343		test	DFCNTRL, DIRECTION jz target_ITloop;
1344		test	SSTAT1, REQINIT	jnz .;
1345		test	DATA_COUNT_ODD, 0x1 jz target_ITloop;
1346		test	SCSIRATE, WIDEXFER jz target_ITloop;
1347		/*
1348		 * Issue an Ignore Wide Residue Message.
1349		 */
1350		mvi	P_MESGIN|BSYO call change_phase;
1351		mvi	MSG_IGN_WIDE_RESIDUE call target_outb;
1352		mvi	1 call target_outb;
1353		jmp	target_ITloop;
1354	} else {
1355		jmp	ITloop;
1356	}
1357
1358if ((ahc->flags & AHC_INITIATORROLE) != 0) {
1359/*
1360 * Command phase.  Set up the DMA registers and let 'er rip.
1361 */
1362p_command:
1363	test	SEQ_FLAGS,IDENTIFY_SEEN	jnz p_command_okay;
1364	mvi	NO_IDENT jmp set_seqint;
1365p_command_okay:
1366
1367	if ((ahc->features & AHC_ULTRA2) != 0) {
1368		bmov	HCNT[0], SCB_CDB_LEN,  1;
1369		bmov	HCNT[1], ALLZEROS, 2;
1370		mvi	SG_CACHE_PRE, LAST_SEG;
1371	} else if ((ahc->features & AHC_CMD_CHAN) != 0) {
1372		bmov	STCNT[0], SCB_CDB_LEN, 1;
1373		bmov	STCNT[1], ALLZEROS, 2;
1374	} else {
1375		mov	STCNT[0], SCB_CDB_LEN;
1376		clr	STCNT[1];
1377		clr	STCNT[2];
1378	}
1379	add	NONE, -13, SCB_CDB_LEN;
1380	mvi	SCB_CDB_STORE jnc p_command_embedded;
1381p_command_from_host:
1382	if ((ahc->features & AHC_ULTRA2) != 0) {
1383		bmov	HADDR[0], SCB_CDB_PTR, 4;
1384		mvi	DFCNTRL, (PRELOADEN|SCSIEN|HDMAEN|DIRECTION);
1385	} else {
1386		if ((ahc->features & AHC_CMD_CHAN) != 0) {
1387			bmov	HADDR[0], SCB_CDB_PTR, 4;
1388			bmov	HCNT, STCNT, 3;
1389		} else {
1390			mvi	DINDEX, HADDR;
1391			mvi	SCB_CDB_PTR call bcopy_4;
1392			mov	SCB_CDB_LEN call set_hcnt;
1393		}
1394		mvi	DFCNTRL, (SCSIEN|SDMAEN|HDMAEN|DIRECTION|FIFORESET);
1395	}
1396	jmp	p_command_loop;
1397p_command_embedded:
1398	/*
1399	 * The data fifo seems to require 4 byte aligned
1400	 * transfers from the sequencer.  Force this to
1401	 * be the case by clearing HADDR[0] even though
1402	 * we aren't going to touch host memory.
1403	 */
1404	clr	HADDR[0];
1405	if ((ahc->features & AHC_ULTRA2) != 0) {
1406		mvi	DFCNTRL, (PRELOADEN|SCSIEN|DIRECTION);
1407		bmov	DFDAT, SCB_CDB_STORE, 12;
1408	} else if ((ahc->features & AHC_CMD_CHAN) != 0) {
1409		if ((ahc->flags & AHC_SCB_BTT) != 0) {
1410			/*
1411			 * On the 7895 the data FIFO will
1412			 * get corrupted if you try to dump
1413			 * data from external SCB memory into
1414			 * the FIFO while it is enabled.  So,
1415			 * fill the fifo and then enable SCSI
1416			 * transfers.
1417			 */
1418			mvi	DFCNTRL, (DIRECTION|FIFORESET);
1419		} else {
1420			mvi	DFCNTRL, (SCSIEN|SDMAEN|DIRECTION|FIFORESET);
1421		}
1422		bmov	DFDAT, SCB_CDB_STORE, 12;
1423		if ((ahc->flags & AHC_SCB_BTT) != 0) {
1424			mvi	DFCNTRL, (SCSIEN|SDMAEN|DIRECTION|FIFOFLUSH);
1425		} else {
1426			or	DFCNTRL, FIFOFLUSH;
1427		}
1428	} else {
1429		mvi	DFCNTRL, (SCSIEN|SDMAEN|DIRECTION|FIFORESET);
1430		call	copy_to_fifo_6;
1431		call	copy_to_fifo_6;
1432		or	DFCNTRL, FIFOFLUSH;
1433	}
1434p_command_loop:
1435	if ((ahc->features & AHC_DT) == 0) {
1436		test	SSTAT0, SDONE jnz . + 2;
1437		test    SSTAT1, PHASEMIS jz p_command_loop;
1438		/*
1439		 * Wait for our ACK to go-away on it's own
1440		 * instead of being killed by SCSIEN getting cleared.
1441		 */
1442		test	SCSISIGI, ACKI jnz .;
1443	} else {
1444		test	DFCNTRL, SCSIEN jnz p_command_loop;
1445	}
1446	and	DFCNTRL, ~(SCSIEN|SDMAEN|HDMAEN);
1447	test	DFCNTRL, (SCSIEN|SDMAEN|HDMAEN) jnz .;
1448	if ((ahc->features & AHC_ULTRA2) != 0) {
1449		/* Drop any residual from the S/G Preload queue */
1450		or	SXFRCTL0, CLRSTCNT;
1451	}
1452	jmp	ITloop;
1453
1454/*
1455 * Status phase.  Wait for the data byte to appear, then read it
1456 * and store it into the SCB.
1457 */
1458p_status:
1459	test	SEQ_FLAGS,IDENTIFY_SEEN	jnz p_status_okay;
1460	mvi	NO_IDENT jmp set_seqint;
1461p_status_okay:
1462	mov	SCB_SCSI_STATUS, SCSIDATL;
1463	jmp	ITloop;
1464
1465/*
1466 * Message out phase.  If MSG_OUT is MSG_IDENTIFYFLAG, build a full
1467 * indentify message sequence and send it to the target.  The host may
1468 * override this behavior by setting the MK_MESSAGE bit in the SCB
1469 * control byte.  This will cause us to interrupt the host and allow
1470 * it to handle the message phase completely on its own.  If the bit
1471 * associated with this target is set, we will also interrupt the host,
1472 * thereby allowing it to send a message on the next selection regardless
1473 * of the transaction being sent.
1474 *
1475 * If MSG_OUT is == HOST_MSG, also interrupt the host and take a message.
1476 * This is done to allow the host to send messages outside of an identify
1477 * sequence while protecting the seqencer from testing the MK_MESSAGE bit
1478 * on an SCB that might not be for the current nexus. (For example, a
1479 * BDR message in responce to a bad reselection would leave us pointed to
1480 * an SCB that doesn't have anything to do with the current target).
1481 *
1482 * Otherwise, treat MSG_OUT as a 1 byte message to send (abort, abort tag,
1483 * bus device reset).
1484 *
1485 * When there are no messages to send, MSG_OUT should be set to MSG_NOOP,
1486 * in case the target decides to put us in this phase for some strange
1487 * reason.
1488 */
1489p_mesgout_retry:
1490	/* Turn on ATN for the retry */
1491	if ((ahc->features & AHC_DT) == 0) {
1492		or	SCSISIGO, ATNO, LASTPHASE;
1493	} else {
1494		mvi	SCSISIGO, ATNO;
1495	}
1496p_mesgout:
1497	mov	SINDEX, MSG_OUT;
1498	cmp	SINDEX, MSG_IDENTIFYFLAG jne p_mesgout_from_host;
1499	test	SCB_CONTROL,MK_MESSAGE	jnz host_message_loop;
1500p_mesgout_identify:
1501	or	SINDEX, MSG_IDENTIFYFLAG|DISCENB, SCB_LUN;
1502	test	SCB_CONTROL, DISCENB jnz . + 2;
1503	and	SINDEX, ~DISCENB;
1504/*
1505 * Send a tag message if TAG_ENB is set in the SCB control block.
1506 * Use SCB_TAG (the position in the kernel's SCB array) as the tag value.
1507 */
1508p_mesgout_tag:
1509	test	SCB_CONTROL,TAG_ENB jz  p_mesgout_onebyte;
1510	mov	SCSIDATL, SINDEX;	/* Send the identify message */
1511	call	phase_lock;
1512	cmp	LASTPHASE, P_MESGOUT	jne p_mesgout_done;
1513	and	SCSIDATL,TAG_ENB|SCB_TAG_TYPE,SCB_CONTROL;
1514	call	phase_lock;
1515	cmp	LASTPHASE, P_MESGOUT	jne p_mesgout_done;
1516	mov	SCB_TAG	jmp p_mesgout_onebyte;
1517/*
1518 * Interrupt the driver, and allow it to handle this message
1519 * phase and any required retries.
1520 */
1521p_mesgout_from_host:
1522	cmp	SINDEX, HOST_MSG	jne p_mesgout_onebyte;
1523	jmp	host_message_loop;
1524
1525p_mesgout_onebyte:
1526	mvi	CLRSINT1, CLRATNO;
1527	mov	SCSIDATL, SINDEX;
1528
1529/*
1530 * If the next bus phase after ATN drops is message out, it means
1531 * that the target is requesting that the last message(s) be resent.
1532 */
1533	call	phase_lock;
1534	cmp	LASTPHASE, P_MESGOUT	je p_mesgout_retry;
1535
1536p_mesgout_done:
1537	mvi	CLRSINT1,CLRATNO;	/* Be sure to turn ATNO off */
1538	mov	LAST_MSG, MSG_OUT;
1539	mvi	MSG_OUT, MSG_NOOP;	/* No message left */
1540	jmp	ITloop;
1541
1542/*
1543 * Message in phase.  Bytes are read using Automatic PIO mode.
1544 */
1545p_mesgin:
1546	mvi	ACCUM		call inb_first;	/* read the 1st message byte */
1547
1548	test	A,MSG_IDENTIFYFLAG	jnz mesgin_identify;
1549	cmp	A,MSG_DISCONNECT	je mesgin_disconnect;
1550	cmp	A,MSG_SAVEDATAPOINTER	je mesgin_sdptrs;
1551	cmp	ALLZEROS,A		je mesgin_complete;
1552	cmp	A,MSG_RESTOREPOINTERS	je mesgin_rdptrs;
1553	cmp	A,MSG_IGN_WIDE_RESIDUE	je mesgin_ign_wide_residue;
1554	cmp	A,MSG_NOOP		je mesgin_done;
1555
1556/*
1557 * Pushed message loop to allow the kernel to
1558 * run it's own message state engine.  To avoid an
1559 * extra nop instruction after signaling the kernel,
1560 * we perform the phase_lock before checking to see
1561 * if we should exit the loop and skip the phase_lock
1562 * in the ITloop.  Performing back to back phase_locks
1563 * shouldn't hurt, but why do it twice...
1564 */
1565host_message_loop:
1566	mvi	HOST_MSG_LOOP call set_seqint;
1567	call	phase_lock;
1568	cmp	RETURN_1, EXIT_MSG_LOOP	je ITloop + 1;
1569	jmp	host_message_loop;
1570
1571mesgin_ign_wide_residue:
1572if ((ahc->features & AHC_WIDE) != 0) {
1573	test	SCSIRATE, WIDEXFER jz mesgin_reject;
1574	/* Pull the residue byte */
1575	mvi	ARG_1	call inb_next;
1576	cmp	ARG_1, 0x01 jne mesgin_reject;
1577	test	SCB_RESIDUAL_SGPTR[0], SG_LIST_NULL jz . + 2;
1578	test	DATA_COUNT_ODD, 0x1	jz mesgin_done;
1579	mvi	IGN_WIDE_RES call set_seqint;
1580	jmp	mesgin_done;
1581}
1582
1583mesgin_reject:
1584	mvi	MSG_MESSAGE_REJECT	call mk_mesg;
1585mesgin_done:
1586	mov	NONE,SCSIDATL;		/*dummy read from latch to ACK*/
1587	jmp	ITloop;
1588
1589mesgin_complete:
1590/*
1591 * We received a "command complete" message.  Put the SCB_TAG into the QOUTFIFO,
1592 * and trigger a completion interrupt.  Before doing so, check to see if there
1593 * is a residual or the status byte is something other than STATUS_GOOD (0).
1594 * In either of these conditions, we upload the SCB back to the host so it can
1595 * process this information.  In the case of a non zero status byte, we
1596 * additionally interrupt the kernel driver synchronously, allowing it to
1597 * decide if sense should be retrieved.  If the kernel driver wishes to request
1598 * sense, it will fill the kernel SCB with a request sense command, requeue
1599 * it to the QINFIFO and tell us not to post to the QOUTFIFO by setting
1600 * RETURN_1 to SEND_SENSE.
1601 */
1602
1603/*
1604 * If ATN is raised, we still want to give the target a message.
1605 * Perhaps there was a parity error on this last message byte.
1606 * Either way, the target should take us to message out phase
1607 * and then attempt to complete the command again.  We should use a
1608 * critical section here to guard against a timeout triggering
1609 * for this command and setting ATN while we are still processing
1610 * the completion.
1611	test	SCSISIGI, ATNI jnz mesgin_done;
1612 */
1613
1614/*
1615 * See if we attempted to deliver a message but the target ingnored us.
1616 */
1617	test	SCB_CONTROL, MK_MESSAGE jz . + 2;
1618	mvi	MKMSG_FAILED call set_seqint;
1619
1620/*
1621 * Check for residuals
1622 */
1623	test	SCB_SGPTR, SG_LIST_NULL jnz check_status;/* No xfer */
1624	test	SCB_SGPTR, SG_FULL_RESID jnz upload_scb;/* Never xfered */
1625	test	SCB_RESIDUAL_SGPTR, SG_LIST_NULL jz upload_scb;
1626check_status:
1627	test	SCB_SCSI_STATUS,0xff	jz complete;	/* Good Status? */
1628upload_scb:
1629	or	SCB_SGPTR, SG_RESID_VALID;
1630	mvi	DMAPARAMS, FIFORESET;
1631	mov	SCB_TAG		call dma_scb;
1632	test	SCB_SCSI_STATUS, 0xff	jz complete;	/* Just a residual? */
1633	mvi	BAD_STATUS call set_seqint;		/* let driver know */
1634	cmp	RETURN_1, SEND_SENSE	jne complete;
1635	call	add_scb_to_free_list;
1636	jmp	await_busfree;
1637complete:
1638	mov	SCB_TAG call complete_post;
1639	jmp	await_busfree;
1640}
1641
1642complete_post:
1643	/* Post the SCBID in SINDEX and issue an interrupt */
1644	call	add_scb_to_free_list;
1645	mov	ARG_1, SINDEX;
1646	if ((ahc->features & AHC_QUEUE_REGS) != 0) {
1647		mov	A, SDSCB_QOFF;
1648	} else {
1649		mov	A, QOUTPOS;
1650	}
1651	mvi	QOUTFIFO_OFFSET call post_byte_setup;
1652	mov	ARG_1 call post_byte;
1653	if ((ahc->features & AHC_QUEUE_REGS) == 0) {
1654		inc 	QOUTPOS;
1655	}
1656	mvi	INTSTAT,CMDCMPLT ret;
1657
1658if ((ahc->flags & AHC_INITIATORROLE) != 0) {
1659/*
1660 * Is it a disconnect message?  Set a flag in the SCB to remind us
1661 * and await the bus going free.  If this is an untagged transaction
1662 * store the SCB id for it in our untagged target table for lookup on
1663 * a reselction.
1664 */
1665mesgin_disconnect:
1666	/*
1667	 * If ATN is raised, we still want to give the target a message.
1668	 * Perhaps there was a parity error on this last message byte
1669	 * or we want to abort this command.  Either way, the target
1670	 * should take us to message out phase and then attempt to
1671	 * disconnect again.
1672	 * XXX - Wait for more testing.
1673	test	SCSISIGI, ATNI jnz mesgin_done;
1674	 */
1675
1676	or	SCB_CONTROL,DISCONNECTED;
1677	if ((ahc->flags & AHC_PAGESCBS) != 0) {
1678		call	add_scb_to_disc_list;
1679	}
1680	test	SCB_CONTROL, TAG_ENB jnz await_busfree;
1681	mov	ARG_1, SCB_TAG;
1682	mov	SAVED_LUN, SCB_LUN;
1683	mov	SCB_SCSIID	call set_busy_target;
1684	jmp	await_busfree;
1685
1686/*
1687 * Save data pointers message:
1688 * Copying RAM values back to SCB, for Save Data Pointers message, but
1689 * only if we've actually been into a data phase to change them.  This
1690 * protects against bogus data in scratch ram and the residual counts
1691 * since they are only initialized when we go into data_in or data_out.
1692 * Ack the message as soon as possible.  For chips without S/G pipelining,
1693 * we can only ack the message after SHADDR has been saved.  On these
1694 * chips, SHADDR increments with every bus transaction, even PIO.
1695 */
1696mesgin_sdptrs:
1697	if ((ahc->features & AHC_ULTRA2) != 0) {
1698		mov	NONE,SCSIDATL;		/*dummy read from latch to ACK*/
1699		test	SEQ_FLAGS, DPHASE	jz ITloop;
1700	} else {
1701		test	SEQ_FLAGS, DPHASE	jz mesgin_done;
1702	}
1703
1704	/*
1705	 * If we are asked to save our position at the end of the
1706	 * transfer, just mark us at the end rather than perform a
1707	 * full save.
1708	 */
1709	test	SCB_RESIDUAL_SGPTR[0], SG_LIST_NULL jz mesgin_sdptrs_full;
1710	or	SCB_SGPTR, SG_LIST_NULL;
1711	if ((ahc->features & AHC_ULTRA2) != 0) {
1712		jmp	ITloop;
1713	} else {
1714		jmp	mesgin_done;
1715	}
1716
1717mesgin_sdptrs_full:
1718
1719	/*
1720	 * The SCB_SGPTR becomes the next one we'll download,
1721	 * and the SCB_DATAPTR becomes the current SHADDR.
1722	 * Use the residual number since STCNT is corrupted by
1723	 * any message transfer.
1724	 */
1725	if ((ahc->features & AHC_CMD_CHAN) != 0) {
1726		bmov	SCB_DATAPTR, SHADDR, 4;
1727		if ((ahc->features & AHC_ULTRA2) == 0) {
1728			mov	NONE,SCSIDATL;	/*dummy read from latch to ACK*/
1729		}
1730		bmov	SCB_DATACNT, SCB_RESIDUAL_DATACNT, 8;
1731	} else {
1732		mvi	DINDEX, SCB_DATAPTR;
1733		mvi	SHADDR call bcopy_4;
1734		mov	NONE,SCSIDATL;	/*dummy read from latch to ACK*/
1735		mvi	SCB_RESIDUAL_DATACNT call bcopy_8;
1736	}
1737	jmp	ITloop;
1738
1739/*
1740 * Restore pointers message?  Data pointers are recopied from the
1741 * SCB anytime we enter a data phase for the first time, so all
1742 * we need to do is clear the DPHASE flag and let the data phase
1743 * code do the rest.
1744 */
1745mesgin_rdptrs:
1746	and	SEQ_FLAGS, ~DPHASE;		/*
1747						 * We'll reload them
1748						 * the next time through
1749						 * the dataphase.
1750						 */
1751	jmp	mesgin_done;
1752
1753/*
1754 * Index into our Busy Target table.  SINDEX and DINDEX are modified
1755 * upon return.  SCBPTR may be modified by this action.
1756 */
1757set_busy_target:
1758	shr	DINDEX, 4, SINDEX;
1759	if ((ahc->flags & AHC_SCB_BTT) != 0) {
1760		mov	SCBPTR, SAVED_LUN;
1761		add	DINDEX, SCB_64_BTT;
1762	} else {
1763		add	DINDEX, BUSY_TARGETS;
1764	}
1765	mov	DINDIR, ARG_1 ret;
1766
1767/*
1768 * Identify message?  For a reconnecting target, this tells us the lun
1769 * that the reconnection is for - find the correct SCB and switch to it,
1770 * clearing the "disconnected" bit so we don't "find" it by accident later.
1771 */
1772mesgin_identify:
1773	/*
1774	 * Determine whether a target is using tagged or non-tagged
1775	 * transactions by first looking at the transaction stored in
1776	 * the busy target array.  If there is no untagged transaction
1777	 * for this target or the transaction is for a different lun, then
1778	 * this must be an untagged transaction.
1779	 */
1780	shr	SINDEX, 4, SAVED_SCSIID;
1781	and	SAVED_LUN, MSG_IDENTIFY_LUNMASK, A;
1782	if ((ahc->flags & AHC_SCB_BTT) != 0) {
1783		add	SINDEX, SCB_64_BTT;
1784		mov	SCBPTR, SAVED_LUN;
1785		if ((ahc->flags & AHC_SEQUENCER_DEBUG) != 0) {
1786			add	NONE, -SCB_64_BTT, SINDEX;
1787			jc	. + 2;
1788			mvi	INTSTAT, OUT_OF_RANGE;
1789			nop;
1790			add	NONE, -(SCB_64_BTT + 16), SINDEX;
1791			jnc	. + 2;
1792			mvi	INTSTAT, OUT_OF_RANGE;
1793			nop;
1794		}
1795	} else {
1796		add	SINDEX, BUSY_TARGETS;
1797		if ((ahc->flags & AHC_SEQUENCER_DEBUG) != 0) {
1798			add	NONE, -BUSY_TARGETS, SINDEX;
1799			jc	. + 2;
1800			mvi	INTSTAT, OUT_OF_RANGE;
1801			nop;
1802			add	NONE, -(BUSY_TARGETS + 16), SINDEX;
1803			jnc	. + 2;
1804			mvi	INTSTAT, OUT_OF_RANGE;
1805			nop;
1806		}
1807	}
1808	mov	ARG_1, SINDIR;
1809	cmp	ARG_1, SCB_LIST_NULL	je snoop_tag;
1810	if ((ahc->flags & AHC_PAGESCBS) != 0) {
1811		mov	ARG_1 call findSCB;
1812	} else {
1813		mov	SCBPTR, ARG_1;
1814	}
1815	if ((ahc->flags & AHC_SCB_BTT) != 0) {
1816		jmp setup_SCB_id_lun_okay;
1817	} else {
1818		/*
1819		 * We only allow one untagged command per-target
1820		 * at a time.  So, if the lun doesn't match, look
1821		 * for a tag message.
1822		 */
1823		mov	A, SCB_LUN;
1824		cmp	SAVED_LUN, A	je setup_SCB_id_lun_okay;
1825		if ((ahc->flags & AHC_PAGESCBS) != 0) {
1826			/*
1827			 * findSCB removes the SCB from the
1828			 * disconnected list, so we must replace
1829			 * it there should this SCB be for another
1830			 * lun.
1831			 */
1832			call	cleanup_scb;
1833		}
1834	}
1835
1836/*
1837 * Here we "snoop" the bus looking for a SIMPLE QUEUE TAG message.
1838 * If we get one, we use the tag returned to find the proper
1839 * SCB.  With SCB paging, we must search for non-tagged
1840 * transactions since the SCB may exist in any slot.  If we're not
1841 * using SCB paging, we can use the tag as the direct index to the
1842 * SCB.
1843 */
1844snoop_tag:
1845	if ((ahc->flags & AHC_SEQUENCER_DEBUG) != 0) {
1846		or	SEQ_FLAGS, 0x80;
1847	}
1848	mov	NONE,SCSIDATL;		/* ACK Identify MSG */
1849	call	phase_lock;
1850	if ((ahc->flags & AHC_SEQUENCER_DEBUG) != 0) {
1851		or	SEQ_FLAGS, 0x1;
1852	}
1853	cmp	LASTPHASE, P_MESGIN	jne not_found;
1854	if ((ahc->flags & AHC_SEQUENCER_DEBUG) != 0) {
1855		or	SEQ_FLAGS, 0x2;
1856	}
1857	cmp	SCSIBUSL,MSG_SIMPLE_Q_TAG jne not_found;
1858get_tag:
1859	if ((ahc->flags & AHC_PAGESCBS) != 0) {
1860		mvi	ARG_1	call inb_next;	/* tag value */
1861		mov	ARG_1	call findSCB;
1862	} else {
1863		mvi	ARG_1	call inb_next;	/* tag value */
1864		mov	SCBPTR, ARG_1;
1865	}
1866
1867/*
1868 * Ensure that the SCB the tag points to is for
1869 * an SCB transaction to the reconnecting target.
1870 */
1871setup_SCB:
1872	if ((ahc->flags & AHC_SEQUENCER_DEBUG) != 0) {
1873		or	SEQ_FLAGS, 0x4;
1874	}
1875	mov	A, SCB_SCSIID;
1876	cmp	SAVED_SCSIID, A	jne not_found_cleanup_scb;
1877	if ((ahc->flags & AHC_SEQUENCER_DEBUG) != 0) {
1878		or	SEQ_FLAGS, 0x8;
1879	}
1880setup_SCB_id_okay:
1881	mov	A, SCB_LUN;
1882	cmp	SAVED_LUN, A	jne not_found_cleanup_scb;
1883setup_SCB_id_lun_okay:
1884	if ((ahc->flags & AHC_SEQUENCER_DEBUG) != 0) {
1885		or	SEQ_FLAGS, 0x10;
1886	}
1887	test	SCB_CONTROL,DISCONNECTED jz not_found_cleanup_scb;
1888	and	SCB_CONTROL,~DISCONNECTED;
1889	test	SCB_CONTROL, TAG_ENB	jnz setup_SCB_tagged;
1890	if ((ahc->flags & AHC_SCB_BTT) != 0) {
1891		mov	A, SCBPTR;
1892	}
1893	mvi	ARG_1, SCB_LIST_NULL;
1894	mov	SAVED_SCSIID	call	set_busy_target;
1895	if ((ahc->flags & AHC_SCB_BTT) != 0) {
1896		mov	SCBPTR, A;
1897	}
1898setup_SCB_tagged:
1899	mvi	SEQ_FLAGS,IDENTIFY_SEEN;	/* make note of IDENTIFY */
1900	call	set_transfer_settings;
1901	/* See if the host wants to send a message upon reconnection */
1902	test	SCB_CONTROL, MK_MESSAGE jz mesgin_done;
1903	mvi	HOST_MSG	call mk_mesg;
1904	jmp	mesgin_done;
1905
1906not_found_cleanup_scb:
1907	if ((ahc->flags & AHC_PAGESCBS) != 0) {
1908		call	cleanup_scb;
1909	}
1910not_found:
1911	mvi	NO_MATCH call set_seqint;
1912	jmp	mesgin_done;
1913
1914mk_mesg:
1915	if ((ahc->features & AHC_DT) == 0) {
1916		or	SCSISIGO, ATNO, LASTPHASE;
1917	} else {
1918		mvi	SCSISIGO, ATNO;
1919	}
1920	mov	MSG_OUT,SINDEX ret;
1921
1922/*
1923 * Functions to read data in Automatic PIO mode.
1924 *
1925 * According to Adaptec's documentation, an ACK is not sent on input from
1926 * the target until SCSIDATL is read from.  So we wait until SCSIDATL is
1927 * latched (the usual way), then read the data byte directly off the bus
1928 * using SCSIBUSL.  When we have pulled the ATN line, or we just want to
1929 * acknowledge the byte, then we do a dummy read from SCISDATL.  The SCSI
1930 * spec guarantees that the target will hold the data byte on the bus until
1931 * we send our ACK.
1932 *
1933 * The assumption here is that these are called in a particular sequence,
1934 * and that REQ is already set when inb_first is called.  inb_{first,next}
1935 * use the same calling convention as inb.
1936 */
1937inb_next_wait_perr:
1938	mvi	PERR_DETECTED call set_seqint;
1939	jmp	inb_next_wait;
1940inb_next:
1941	mov	NONE,SCSIDATL;		/*dummy read from latch to ACK*/
1942inb_next_wait:
1943	/*
1944	 * If there is a parity error, wait for the kernel to
1945	 * see the interrupt and prepare our message response
1946	 * before continuing.
1947	 */
1948	test	SSTAT1, REQINIT	jz inb_next_wait;
1949	test	SSTAT1, SCSIPERR jnz inb_next_wait_perr;
1950inb_next_check_phase:
1951	and	LASTPHASE, PHASE_MASK, SCSISIGI;
1952	cmp	LASTPHASE, P_MESGIN jne mesgin_phasemis;
1953inb_first:
1954	mov	DINDEX,SINDEX;
1955	mov	DINDIR,SCSIBUSL	ret;		/*read byte directly from bus*/
1956inb_last:
1957	mov	NONE,SCSIDATL ret;		/*dummy read from latch to ACK*/
1958}
1959
1960if ((ahc->flags & AHC_TARGETROLE) != 0) {
1961/*
1962 * Change to a new phase.  If we are changing the state of the I/O signal,
1963 * from out to in, wait an additional data release delay before continuing.
1964 */
1965change_phase:
1966	/* Wait for preceeding I/O session to complete. */
1967	test	SCSISIGI, ACKI jnz .;
1968
1969	/* Change the phase */
1970	and	DINDEX, IOI, SCSISIGI;
1971	mov	SCSISIGO, SINDEX;
1972	and	A, IOI, SINDEX;
1973
1974	/*
1975	 * If the data direction has changed, from
1976	 * out (initiator driving) to in (target driving),
1977	 * we must wait at least a data release delay plus
1978	 * the normal bus settle delay. [SCSI III SPI 10.11.0]
1979	 */
1980	cmp 	DINDEX, A je change_phase_wait;
1981	test	SINDEX, IOI jz change_phase_wait;
1982	call	change_phase_wait;
1983change_phase_wait:
1984	nop;
1985	nop;
1986	nop;
1987	nop ret;
1988
1989/*
1990 * Send a byte to an initiator in Automatic PIO mode.
1991 */
1992target_outb:
1993	or	SXFRCTL0, SPIOEN;
1994	test	SSTAT0, SPIORDY	jz .;
1995	mov	SCSIDATL, SINDEX;
1996	test	SSTAT0, SPIORDY	jz .;
1997	and	SXFRCTL0, ~SPIOEN ret;
1998}
1999
2000/*
2001 * Locate a disconnected SCB by SCBID.  Upon return, SCBPTR and SINDEX will
2002 * be set to the position of the SCB.  If the SCB cannot be found locally,
2003 * it will be paged in from host memory.  RETURN_2 stores the address of the
2004 * preceding SCB in the disconnected list which can be used to speed up
2005 * removal of the found SCB from the disconnected list.
2006 */
2007if ((ahc->flags & AHC_PAGESCBS) != 0) {
2008BEGIN_CRITICAL;
2009findSCB:
2010	mov	A, SINDEX;			/* Tag passed in SINDEX */
2011	cmp	DISCONNECTED_SCBH, SCB_LIST_NULL je findSCB_notFound;
2012	mov	SCBPTR, DISCONNECTED_SCBH;	/* Initialize SCBPTR */
2013	mvi	ARG_2, SCB_LIST_NULL;		/* Head of list */
2014	jmp	findSCB_loop;
2015findSCB_next:
2016	cmp	SCB_NEXT, SCB_LIST_NULL je findSCB_notFound;
2017	mov	ARG_2, SCBPTR;
2018	mov	SCBPTR,SCB_NEXT;
2019findSCB_loop:
2020	cmp	SCB_TAG, A	jne findSCB_next;
2021rem_scb_from_disc_list:
2022	cmp	ARG_2, SCB_LIST_NULL	je rHead;
2023	mov	DINDEX, SCB_NEXT;
2024	mov	SINDEX, SCBPTR;
2025	mov	SCBPTR, ARG_2;
2026	mov	SCB_NEXT, DINDEX;
2027	mov	SCBPTR, SINDEX ret;
2028rHead:
2029	mov	DISCONNECTED_SCBH,SCB_NEXT ret;
2030END_CRITICAL;
2031findSCB_notFound:
2032	/*
2033	 * We didn't find it.  Page in the SCB.
2034	 */
2035	mov	ARG_1, A; /* Save tag */
2036	mov	ALLZEROS call get_free_or_disc_scb;
2037	mvi	DMAPARAMS, HDMAEN|DIRECTION|FIFORESET;
2038	mov	ARG_1	jmp dma_scb;
2039}
2040
2041/*
2042 * Prepare the hardware to post a byte to host memory given an
2043 * index of (A + (256 * SINDEX)) and a base address of SHARED_DATA_ADDR.
2044 */
2045post_byte_setup:
2046	mov	ARG_2, SINDEX;
2047	if ((ahc->features & AHC_CMD_CHAN) != 0) {
2048		mvi	DINDEX, CCHADDR;
2049		mvi	SHARED_DATA_ADDR call	set_1byte_addr;
2050		mvi	CCHCNT, 1;
2051		mvi	CCSCBCTL, CCSCBRESET ret;
2052	} else {
2053		mvi	DINDEX, HADDR;
2054		mvi	SHARED_DATA_ADDR call	set_1byte_addr;
2055		mvi	1	call set_hcnt;
2056		mvi	DFCNTRL, FIFORESET ret;
2057	}
2058
2059post_byte:
2060	if ((ahc->features & AHC_CMD_CHAN) != 0) {
2061		bmov	CCSCBRAM, SINDEX, 1;
2062		or	CCSCBCTL, CCSCBEN|CCSCBRESET;
2063		test	CCSCBCTL, CCSCBDONE jz .;
2064		clr	CCSCBCTL ret;
2065	} else {
2066		mov	DFDAT, SINDEX;
2067		or	DFCNTRL, HDMAEN|FIFOFLUSH;
2068		jmp	dma_finish;
2069	}
2070
2071phase_lock_perr:
2072	mvi	PERR_DETECTED call set_seqint;
2073phase_lock:
2074	/*
2075	 * If there is a parity error, wait for the kernel to
2076	 * see the interrupt and prepare our message response
2077	 * before continuing.
2078	 */
2079	test	SSTAT1, REQINIT jz phase_lock;
2080	test	SSTAT1, SCSIPERR jnz phase_lock_perr;
2081phase_lock_latch_phase:
2082	if ((ahc->features & AHC_DT) == 0) {
2083		and	SCSISIGO, PHASE_MASK, SCSISIGI;
2084	}
2085	and	LASTPHASE, PHASE_MASK, SCSISIGI ret;
2086
2087if ((ahc->features & AHC_CMD_CHAN) == 0) {
2088set_hcnt:
2089	mov	HCNT[0], SINDEX;
2090clear_hcnt:
2091	clr	HCNT[1];
2092	clr	HCNT[2] ret;
2093
2094set_stcnt_from_hcnt:
2095	mov	STCNT[0], HCNT[0];
2096	mov	STCNT[1], HCNT[1];
2097	mov	STCNT[2], HCNT[2] ret;
2098
2099bcopy_8:
2100	mov	DINDIR, SINDIR;
2101bcopy_7:
2102	mov	DINDIR, SINDIR;
2103	mov	DINDIR, SINDIR;
2104bcopy_5:
2105	mov	DINDIR, SINDIR;
2106bcopy_4:
2107	mov	DINDIR, SINDIR;
2108bcopy_3:
2109	mov	DINDIR, SINDIR;
2110	mov	DINDIR, SINDIR;
2111	mov	DINDIR, SINDIR ret;
2112}
2113
2114if ((ahc->flags & AHC_TARGETROLE) != 0) {
2115/*
2116 * Setup addr assuming that A is an index into
2117 * an array of 32byte objects, SINDEX contains
2118 * the base address of that array, and DINDEX
2119 * contains the base address of the location
2120 * to store the indexed address.
2121 */
2122set_32byte_addr:
2123	shr	ARG_2, 3, A;
2124	shl	A, 5;
2125	jmp	set_1byte_addr;
2126}
2127
2128/*
2129 * Setup addr assuming that A is an index into
2130 * an array of 64byte objects, SINDEX contains
2131 * the base address of that array, and DINDEX
2132 * contains the base address of the location
2133 * to store the indexed address.
2134 */
2135set_64byte_addr:
2136	shr	ARG_2, 2, A;
2137	shl	A, 6;
2138
2139/*
2140 * Setup addr assuming that A + (ARG_2 * 256) is an
2141 * index into an array of 1byte objects, SINDEX contains
2142 * the base address of that array, and DINDEX contains
2143 * the base address of the location to store the computed
2144 * address.
2145 */
2146set_1byte_addr:
2147	add     DINDIR, A, SINDIR;
2148	mov     A, ARG_2;
2149	adc	DINDIR, A, SINDIR;
2150	clr	A;
2151	adc	DINDIR, A, SINDIR;
2152	adc	DINDIR, A, SINDIR ret;
2153
2154/*
2155 * Either post or fetch an SCB from host memory based on the
2156 * DIRECTION bit in DMAPARAMS. The host SCB index is in SINDEX.
2157 */
2158dma_scb:
2159	mov	A, SINDEX;
2160	if ((ahc->features & AHC_CMD_CHAN) != 0) {
2161		mvi	DINDEX, CCHADDR;
2162		mvi	HSCB_ADDR call set_64byte_addr;
2163		mov	CCSCBPTR, SCBPTR;
2164		test	DMAPARAMS, DIRECTION jz dma_scb_tohost;
2165		if ((ahc->flags & AHC_SCB_BTT) != 0) {
2166			mvi	CCHCNT, SCB_DOWNLOAD_SIZE_64;
2167		} else {
2168			mvi	CCHCNT, SCB_DOWNLOAD_SIZE;
2169		}
2170		mvi	CCSCBCTL, CCARREN|CCSCBEN|CCSCBDIR|CCSCBRESET;
2171		cmp	CCSCBCTL, CCSCBDONE|ARRDONE|CCARREN|CCSCBEN|CCSCBDIR jne .;
2172		jmp	dma_scb_finish;
2173dma_scb_tohost:
2174		mvi	CCHCNT, SCB_UPLOAD_SIZE;
2175		if ((ahc->features & AHC_ULTRA2) == 0) {
2176			mvi	CCSCBCTL, CCSCBRESET;
2177			bmov	CCSCBRAM, SCB_BASE, SCB_UPLOAD_SIZE;
2178			or	CCSCBCTL, CCSCBEN|CCSCBRESET;
2179			test	CCSCBCTL, CCSCBDONE jz .;
2180		} else if ((ahc->bugs & AHC_SCBCHAN_UPLOAD_BUG) != 0) {
2181			mvi	CCSCBCTL, CCARREN|CCSCBRESET;
2182			cmp	CCSCBCTL, ARRDONE|CCARREN jne .;
2183			mvi	CCHCNT, SCB_UPLOAD_SIZE;
2184			mvi	CCSCBCTL, CCSCBEN|CCSCBRESET;
2185			cmp	CCSCBCTL, CCSCBDONE|CCSCBEN jne .;
2186		} else {
2187			mvi	CCSCBCTL, CCARREN|CCSCBEN|CCSCBRESET;
2188			cmp	CCSCBCTL, CCSCBDONE|ARRDONE|CCARREN|CCSCBEN jne .;
2189		}
2190dma_scb_finish:
2191		clr	CCSCBCTL;
2192		test	CCSCBCTL, CCARREN|CCSCBEN jnz .;
2193		ret;
2194	} else {
2195		mvi	DINDEX, HADDR;
2196		mvi	HSCB_ADDR call set_64byte_addr;
2197		mvi	SCB_DOWNLOAD_SIZE call set_hcnt;
2198		mov	DFCNTRL, DMAPARAMS;
2199		test	DMAPARAMS, DIRECTION	jnz dma_scb_fromhost;
2200		/* Fill it with the SCB data */
2201copy_scb_tofifo:
2202		mvi	SINDEX, SCB_BASE;
2203		add	A, SCB_DOWNLOAD_SIZE, SINDEX;
2204copy_scb_tofifo_loop:
2205		call	copy_to_fifo_8;
2206		cmp	SINDEX, A jne copy_scb_tofifo_loop;
2207		or	DFCNTRL, HDMAEN|FIFOFLUSH;
2208		jmp	dma_finish;
2209dma_scb_fromhost:
2210		mvi	DINDEX, SCB_BASE;
2211		if ((ahc->bugs & AHC_PCI_2_1_RETRY_BUG) != 0) {
2212			/*
2213			 * The PCI module will only issue a PCI
2214			 * retry if the data FIFO is empty.  If the
2215			 * host disconnects in the middle of a
2216			 * transfer, we must empty the fifo of all
2217			 * available data to force the chip to
2218			 * continue the transfer.  This does not
2219			 * happen for SCSI transfers as the SCSI module
2220			 * will drain the FIFO as data is made available.
2221			 * When the hang occurs, we know that a multiple
2222			 * of 8 bytes are in the FIFO because the PCI
2223			 * module has an 8 byte input latch that only
2224			 * dumps to the FIFO when HCNT == 0 or the
2225			 * latch is full.
2226			 */
2227			clr	A;
2228			/* Wait for at least 8 bytes of data to arrive. */
2229dma_scb_hang_fifo:
2230			test	DFSTATUS, FIFOQWDEMP jnz dma_scb_hang_fifo;
2231dma_scb_hang_wait:
2232			test	DFSTATUS, MREQPEND jnz dma_scb_hang_wait;
2233			test	DFSTATUS, HDONE	jnz dma_scb_hang_dma_done;
2234			test	DFSTATUS, HDONE	jnz dma_scb_hang_dma_done;
2235			test	DFSTATUS, HDONE	jnz dma_scb_hang_dma_done;
2236			/*
2237			 * The PCI module no longer intends to perform
2238			 * a PCI transaction.  Drain the fifo.
2239			 */
2240dma_scb_hang_dma_drain_fifo:
2241			not	A, HCNT;
2242			add	A, SCB_DOWNLOAD_SIZE+SCB_BASE+1;
2243			and	A, ~0x7;
2244			mov	DINDIR,DFDAT;
2245			cmp	DINDEX, A jne . - 1;
2246			cmp	DINDEX, SCB_DOWNLOAD_SIZE+SCB_BASE
2247				je	dma_finish_nowait;
2248			/* Restore A as the lines left to transfer. */
2249			add	A, -SCB_BASE, DINDEX;
2250			shr	A, 3;
2251			jmp	dma_scb_hang_fifo;
2252dma_scb_hang_dma_done:
2253			and	DFCNTRL, ~HDMAEN;
2254			test	DFCNTRL, HDMAEN jnz .;
2255			add	SEQADDR0, A;
2256		} else {
2257			call	dma_finish;
2258		}
2259		/* If we were putting the SCB, we are done */
2260		call	dfdat_in_8;
2261		call	dfdat_in_8;
2262		call	dfdat_in_8;
2263dfdat_in_8:
2264		mov	DINDIR,DFDAT;
2265dfdat_in_7:
2266		mov	DINDIR,DFDAT;
2267		mov	DINDIR,DFDAT;
2268		mov	DINDIR,DFDAT;
2269		mov	DINDIR,DFDAT;
2270		mov	DINDIR,DFDAT;
2271dfdat_in_2:
2272		mov	DINDIR,DFDAT;
2273		mov	DINDIR,DFDAT ret;
2274	}
2275
2276copy_to_fifo_8:
2277	mov	DFDAT,SINDIR;
2278	mov	DFDAT,SINDIR;
2279copy_to_fifo_6:
2280	mov	DFDAT,SINDIR;
2281copy_to_fifo_5:
2282	mov	DFDAT,SINDIR;
2283copy_to_fifo_4:
2284	mov	DFDAT,SINDIR;
2285	mov	DFDAT,SINDIR;
2286	mov	DFDAT,SINDIR;
2287	mov	DFDAT,SINDIR ret;
2288
2289/*
2290 * Wait for DMA from host memory to data FIFO to complete, then disable
2291 * DMA and wait for it to acknowledge that it's off.
2292 */
2293dma_finish:
2294	test	DFSTATUS,HDONE	jz dma_finish;
2295dma_finish_nowait:
2296	/* Turn off DMA */
2297	and	DFCNTRL, ~HDMAEN;
2298	test	DFCNTRL, HDMAEN jnz .;
2299	ret;
2300
2301/*
2302 * Restore an SCB that failed to match an incoming reselection
2303 * to the correct/safe state.  If the SCB is for a disconnected
2304 * transaction, it must be returned to the disconnected list.
2305 * If it is not in the disconnected state, it must be free.
2306 */
2307cleanup_scb:
2308	if ((ahc->flags & AHC_PAGESCBS) != 0) {
2309		test	SCB_CONTROL,DISCONNECTED jnz add_scb_to_disc_list;
2310	}
2311add_scb_to_free_list:
2312	if ((ahc->flags & AHC_PAGESCBS) != 0) {
2313BEGIN_CRITICAL;
2314		mov	SCB_NEXT, FREE_SCBH;
2315		mvi	SCB_TAG, SCB_LIST_NULL;
2316		mov	FREE_SCBH, SCBPTR ret;
2317END_CRITICAL;
2318	} else {
2319		mvi	SCB_TAG, SCB_LIST_NULL ret;
2320	}
2321
2322if ((ahc->flags & AHC_39BIT_ADDRESSING) != 0) {
2323set_hhaddr:
2324	or	DSCOMMAND1, HADDLDSEL0;
2325	and	HADDR, SG_HIGH_ADDR_BITS, SINDEX;
2326	and	DSCOMMAND1, ~HADDLDSEL0 ret;
2327}
2328
2329if ((ahc->flags & AHC_PAGESCBS) != 0) {
2330get_free_or_disc_scb:
2331BEGIN_CRITICAL;
2332	cmp	FREE_SCBH, SCB_LIST_NULL jne dequeue_free_scb;
2333	cmp	DISCONNECTED_SCBH, SCB_LIST_NULL jne dequeue_disc_scb;
2334return_error:
2335	mvi	NO_FREE_SCB call set_seqint;
2336	mvi	SINDEX, SCB_LIST_NULL	ret;
2337dequeue_disc_scb:
2338	mov	SCBPTR, DISCONNECTED_SCBH;
2339	mov	DISCONNECTED_SCBH, SCB_NEXT;
2340END_CRITICAL;
2341	mvi	DMAPARAMS, FIFORESET;
2342	mov	SCB_TAG	jmp dma_scb;
2343BEGIN_CRITICAL;
2344dequeue_free_scb:
2345	mov	SCBPTR, FREE_SCBH;
2346	mov	FREE_SCBH, SCB_NEXT ret;
2347END_CRITICAL;
2348
2349add_scb_to_disc_list:
2350/*
2351 * Link this SCB into the DISCONNECTED list.  This list holds the
2352 * candidates for paging out an SCB if one is needed for a new command.
2353 * Modifying the disconnected list is a critical(pause dissabled) section.
2354 */
2355BEGIN_CRITICAL;
2356	mov	SCB_NEXT, DISCONNECTED_SCBH;
2357	mov	DISCONNECTED_SCBH, SCBPTR ret;
2358END_CRITICAL;
2359}
2360set_seqint:
2361	mov	INTSTAT, SINDEX;
2362	nop;
2363return:
2364	ret;
2365