aic7xxx.c:

	Filter incoming transfer negotiation requests to ensure they
	never exceed the settings specified by the user.

	In restart sequencer attempt to deal with a bug in the aic7895.
	If a third party reset occurs at just the right time, the
	stack register can lock up.  When restarting the sequencer
	after handling the SCSI reset, poke SEQADDR1 before resting
	the sequencers program counter.

	When something strange happens, dump the card's transaction
	state via ahc_dump_card_state().  This should aid in debugging.

	Handle request sense transactions via the QINFIFO instead of
	attaching them to the waiting queue directly.  The waiting
	queue consumes card SCB resources and, in the pathological case
	of every target on the bus beating our selection attemps and
	issuing a check condition, could have caused us to run out
	of SCBs.  I have never seen this happen, and only early
	cards with 3 or 4 SCBs had any real chance of ever getting
	into this state.

	Add additional sequencer interrupt codes to support firmware
	diagnostics.  The diagnostic code is enabled with the
	AHC_DEBUG_SEQUENCER kernel option.

	Make it possible to switch into and out of target mode on
	the fly.  The card comes up by default as an initiator but
	will switch into target mode as soon as an enable lun operation
	is performed.  As always, target mode behavior is gated
	by the AHC_TMODE_ENABLE kernel option so most users will
	not be affected by this change.

	In ahc_update_target_msg_request(), also issue a new
	request if the ppr_options have changed.

	Never issue a PPR as a target.  It is forbidden by the spec.

	Correct a bug in ahc_parse_msg() that prevented us from
	responding to PPR messages as a target.

	Mark SCBs that are on the untagged queue with a flag instead
	of checking several fields in the SCB to see if the SCB should
	be on the queue.  This makes it easier for things like automatic
	request sense requests to be queued without touching the
	untagged queues even though they are untagged requests.

	When dealing with ignore wide residue messages that occur
	in the middle of a transfer, reset HADDR, not SHADDR for
	non-ultra2 chips.  Although SHADDR is where the firmware
	fetches the ending transfer address for a save data pointers
	request, it is readonly. Setting HADDR has the side effect
	of also updating SHADDR.

	Cleanup the output of ahc_dump_card_state() by nulling out the
	free scb list in the non-paging case.  The free list is only
	used if we must page SCBs.

	Correct the transmission of cdbs > 12 bytes in length.  When
	swapping HSCBs prior to notifing the sequencer of the new
	transaction, the bus address pointer for the cdb must also
	be recalculated to reflect its new location.  We now defer
	the calculation of the cdb address until just before queing
	it to the card.

	When pulling transfer negotiation settings out of scratch
	ram, convert 5MHz/clock doubled settings to 10MHz.

	Add a new function ahc_qinfifo_requeue_tail() for use by
	error recovery actions and auto-request sense operations.
	These operations always occur when the sequencer is paused,
	so we can avoid the extra expense incurred in the normal
	SCB queue method.

	Use the BMOV instruction for all single byte moves on
	controllers that support it.  The bmov instruction is
	twice as fast as an AND with an immediate of 0xFF as
	is used on older controllers.

	Correct a few bugs in ahc_dump_card_state().  If we have
	hardware assisted queue registers, use them to get the
	sequencer's idea of the head of the queue.  When enumerating
	the untagged queue, it helps to use the correct index for
	the queue.

aic7xxx.h:

	Indicate via a feature flag, which controllers can take
	on both the target and the initiator role at the same time.

	Add the AHC_SEQUENCER_DEBUG flag.

	Add the SCB_CDB32_PTR flag used for dealing with cdbs
	with lengths between 13 and 32 bytes.

	Add new prototypes.

aic7xxx.reg:
	Allow the SCSIBUSL register to be written to.  This is
	required to fix a selection timeout problem on the 7892/99.

	Cleanup the sequencer interrupt codes so that all debugging
	codes are grouped at the end of the list.

	Correct the definition of the ULTRA_ENB and DISC_DSB locations
	in scratch ram.  This prevented the driver from properly honoring
	these settings when no serial eeprom was available.

	Remove an unused sequencer flag.

aic7xxx.seq:
	Just before a potential select-out, clear the SCSIBUSL
	register.  Occasionally, during a selection timeout, the
	contents of the register may be presented on the bus,
	causing much confusion.

	Add sequencer diagnostic code to detect software and or
	hardware bugs.  The code attempts to verify most list
	operations so any corruption is caught before it occurs.
	We also track information about why a particular reconnection
	request was rejected.

	Don't clobber the digital REQ/ACK filter setting in SXFRCTL0
	when clearing the channel.

	Fix a target mode bug that would cause us to return busy
	status instead of queue full in respnse to a tagged transaction.

	Cleanup the overrun case.  It turns out that by simply
	butting the chip in bitbucket mode, it will ack any
	bytes until the phase changes.  This drasticaly simplifies
	things.

	Prior to leaving the data phase, make sure that the S/G
	preload queue is empty.

	Remove code to place a request sense request on the waiting
	queue.  This is all handled by the kernel now.

	Change the semantics of "findSCB".  In the past, findSCB
	ensured that a freshly paged in SCB appeared on the disconnected
	list.  The problem with this is that there is no guarantee that
	the paged in SCB is for a disconnected transation.  We now
	defer any list manipulation to the caller who usually discards
	the SCB via the free list.

	Inline some busy target table operations.

	Add a critical section to protect adding an SCB to
	the disconnected list.

aic7xxx_freebsd.c:
	Handle changes in the transfer negotiation setting API
	to filter incoming requests.  No filtering is necessary
	for "goal" requests from the XPT.

	Set the SCB_CDB32_PTR flag when queing a transaction with
	a large cdb.

	In ahc_timeout, only take action if the active SCB is
	the timedout SCB.  This deals with the case of two
	transactions to the same device with different timeout
	values.

	Use ahc_qinfifo_requeu_tail() instead of home grown
	version.

aic7xxx_inline.h:
	Honor SCB_CDB32_PTR when queuing a new request.

aic7xxx_pci.c:
	Use the maximum data fifo threshold for all chips.

1 files changed, 130 insertions, 124 deletions

diff --git a/sys/dev/aic7xxx/aic7xxx.seq b/sys/dev/aic7xxx/aic7xxx.seq
index 33af1a5..f300676 100644
--- a/sys/dev/aic7xxx/aic7xxx.seq
+++ b/sys/dev/aic7xxx/aic7xxx.seq
@@ -57,9 +57,7 @@
 poll_for_work:
 	call	clear_target_state;
 	and	SXFRCTL0, ~SPIOEN;
-	if ((ahc->features & AHC_QUEUE_REGS) == 0) {
-		mov	A, QINPOS;
-	}
+	clr	SCSIBUSL;
 poll_for_work_loop:
 	test	SSTAT0, SELDO|SELDI	jnz selection;
 	test	SCSISEQ, ENSELO	jnz poll_for_work_loop;
@@ -82,6 +80,7 @@ BEGIN_CRITICAL
 		test	QOFF_CTLSTA, SCB_AVAIL jz poll_for_work_loop;
 		mov	NONE, SNSCB_QOFF;
 	} else {
+		mov	A, QINPOS;
 		cmp	KERNEL_QINPOS, A je poll_for_work_loop;
 		inc	QINPOS;
 	}
@@ -114,6 +113,14 @@ dma_queued_scb:
 	mov	A, ARG_1;
 BEGIN_CRITICAL
 	cmp	NEXT_QUEUED_SCB, A jne abort_qinscb;
+	if ((ahc->flags & AHC_SEQUENCER_DEBUG) != 0) {
+		if ((ahc->flags & AHC_PAGESCBS) == 0) {
+			cmp	SCBPTR, A je . + 2;
+			mvi	INTSTAT, SCBPTR_MISMATCH;
+		}
+		cmp	SCB_TAG, A je . + 2;
+		mvi	INTSTAT, SCB_MISMATCH;
+	}
 	mov	NEXT_QUEUED_SCB, SCB_NEXT;
 	mov	SCB_NEXT,WAITING_SCBH;
 	mov	WAITING_SCBH, SCBPTR;
@@ -127,7 +134,7 @@ start_waiting:
 	jmp	poll_for_work_loop;
 
 abort_qinscb:
-	mvi	INTSTAT, TRACEPOINT;
+	mvi	INTSTAT, ABORT_QINSCB;
 	call	add_scb_to_free_list;
 	jmp	poll_for_work_loop;
 
@@ -146,7 +153,7 @@ initialize_scsiid:
 	} else {
 		mov	SCSIID, SCB_SCSIID;
 	}
-	if ((ahc->flags & AHC_TARGETMODE) != 0) {
+	if ((ahc->flags & AHC_TARGETROLE) != 0) {
 		mov	SINDEX, SCSISEQ_TEMPLATE;
 		test	SCB_CONTROL, TARGET_SCB jz . + 2;
 		or	SINDEX, TEMODE;
@@ -162,7 +169,7 @@ initialize_scsiid:
  * a valid SCB for the target we wish to talk to.
  */
 initialize_channel:
-	or	SXFRCTL0, CLRSTCNT|CLRCHN, SINDEX;
+	or	SXFRCTL0, SPIOEN|CLRSTCNT|CLRCHN;
 set_transfer_settings:
 	if ((ahc->features & AHC_ULTRA) != 0) {
 		test	SCB_CONTROL, ULTRAENB jz . + 2;
@@ -188,8 +195,8 @@ selection:
 	test	SSTAT0,SELDO	jnz select_out;
 	mvi	CLRSINT0, CLRSELDI;
 select_in:
-	if ((ahc->flags & AHC_TARGETMODE) != 0) {
-		if ((ahc->flags & AHC_INITIATORMODE) != 0) {
+	if ((ahc->flags & AHC_TARGETROLE) != 0) {
+		if ((ahc->flags & AHC_INITIATORROLE) != 0) {
 			test	SSTAT0, TARGET	jz initiator_reselect;
 		}
 
@@ -332,7 +339,7 @@ ident_messages_done:
 		}
 		cmp	TQINPOS, A jne tqinfifo_has_space;
 		mvi	P_STATUS|BSYO call change_phase;
-		test	SEQ_FLAGS, TARGET_CMD_IS_TAGGED jnz . + 3;
+		test	SEQ_FLAGS, TARGET_CMD_IS_TAGGED jz . + 3;
 		mvi	STATUS_QUEUE_FULL call target_outb;
 		jmp	target_busfree_wait;
 		mvi	STATUS_BUSY call target_outb;
@@ -366,7 +373,7 @@ target_inb:
 		mov	DINDEX, SCSIDATL ret;
 	}
 
-if ((ahc->flags & AHC_INITIATORMODE) != 0) {
+if ((ahc->flags & AHC_INITIATORROLE) != 0) {
 /*
  * Reselection has been initiated by a target. Make a note that we've been
  * reselected, but haven't seen an IDENTIFY message from the target yet.
@@ -399,11 +406,15 @@ select_out:
 	and	SCSISEQ, TEMODE|ENSELI|ENRSELI|ENAUTOATNP, SCSISEQ;
 	mvi	CLRSINT0, CLRSELDO;
 	mov	SCBPTR, WAITING_SCBH;
+	if ((ahc->flags & AHC_SEQUENCER_DEBUG) != 0) {
+		cmp	SCB_TAG, SCB_LIST_NULL jne . + 2;
+		mvi	INTSTAT, BOGUS_TAG;
+	}
 	mov	WAITING_SCBH,SCB_NEXT;
 	mov	SAVED_SCSIID, SCB_SCSIID;
 	mov	SAVED_LUN, SCB_LUN;
-	mvi	SPIOEN call	initialize_channel;
-	if ((ahc->flags & AHC_TARGETMODE) != 0) {
+	call	initialize_channel;
+	if ((ahc->flags & AHC_TARGETROLE) != 0) {
 		test	SSTAT0, TARGET	jz initiator_select;
 
 		/*
@@ -476,6 +487,7 @@ target_busfree_wait:
 		test	SCSISIGI, ACKI jnz .;
 target_busfree:
 		and	SIMODE1, ~ENBUSFREE;
+		clr	SCSIBUSL;
 		clr	SCSISIGO;
 		mvi	LASTPHASE, P_BUSFREE;
 		call	complete_target_cmd;
@@ -501,7 +513,7 @@ target_cmdphase:
 		 * the first byte.
 		 */
 		shr	A, CMD_GROUP_CODE_SHIFT;
-		add	SINDEX, TARG_SCSIRATE, A;
+		add	SINDEX, CMDSIZE_TABLE, A;
 		mov	A, SINDIR;
 
 		test	A, 0xFF jz command_phase_done;
@@ -569,7 +581,7 @@ complete_target_cmd:
 		mvi	INTSTAT,CMDCMPLT ret;
 	}
 
-if ((ahc->flags & AHC_INITIATORMODE) != 0) {
+if ((ahc->flags & AHC_INITIATORROLE) != 0) {
 initiator_select:
 	/*
 	 * As soon as we get a successful selection, the target
@@ -602,6 +614,7 @@ ITloop:
 await_busfree:
 	and	SIMODE1, ~ENBUSFREE;
 	mov	NONE, SCSIDATL;		/* Ack the last byte */
+	clr	SCSIBUSL;		/* Prevent bit leakage durint SELTO */
 	and	SXFRCTL0, ~SPIOEN;
 	test	SSTAT1,REQINIT|BUSFREE	jz .;
 	test	SSTAT1, BUSFREE jnz poll_for_work;
@@ -615,7 +628,7 @@ clear_target_state:
 	 * clear DFCNTRL too.
 	 */
 	clr	DFCNTRL;
-	mvi	SXFRCTL0, CLRSTCNT|CLRCHN;
+	or	SXFRCTL0, CLRSTCNT|CLRCHN;
 
 	/*
 	 * We don't know the target we will connect to,
@@ -817,23 +830,17 @@ data_phase_loop:
 	test	SCB_RESIDUAL_SGPTR[0], SG_LIST_NULL jz data_phase_inbounds;
 
 	/*
-	 * Turn on 'Bit Bucket' mode, set the transfer count to
-	 * 16meg and let the target run until it changes phase.
-	 * When the transfer completes, notify the host that we
-	 * had an overrun.
+	 * Turn on `Bit Bucket' mode, wait until the target takes
+	 * us to another phase, and then notify the host.
 	 */
+	and	DMAPARAMS, DIRECTION;
+	mov	DFCNTRL, DMAPARAMS;
 	or	SXFRCTL1,BITBUCKET;
-	and	DMAPARAMS, ~(HDMAEN|SDMAEN);
-	if ((ahc->features & AHC_ULTRA2) != 0) {
-		bmov	HCNT, ALLONES, 3;
-		or	SXFRCTL0, CLRCHN|CLRSTCNT;/* Ensure FIFO empty */
-	} else if ((ahc->features & AHC_CMD_CHAN) != 0) {
-		bmov	STCNT, ALLONES, 3;
-	} else {
-		mvi	STCNT[0], 0xFF;
-		mvi	STCNT[1], 0xFF;
-		mvi	STCNT[2], 0xFF;
-	}
+	test	SSTAT1,PHASEMIS	jz .;
+	and	SXFRCTL1, ~BITBUCKET;
+	mvi	INTSTAT,DATA_OVERRUN;
+	jmp	ITloop;
+
 data_phase_inbounds:
 	if ((ahc->features & AHC_ULTRA2) != 0) {
 		mov	SINDEX, SCB_RESIDUAL_SGPTR[0];
@@ -889,8 +896,6 @@ ultra2_dmahalt:
 		and     DFCNTRL, ~(SCSIEN|HDMAEN);
 		test	DFCNTRL, HDMAEN jnz .;
 
-		test	SXFRCTL1,BITBUCKET jnz data_phase_finish;
-
 		/*
 		 * If, by chance, we stopped before being able
 		 * to fetch additional segments for this transfer,
@@ -946,7 +951,7 @@ sgptr_fixup_done:
 			test	MWI_RESIDUAL, 0xFF jnz dma_mid_sg;
 		}
 		test	SCB_RESIDUAL_DATACNT[3], SG_LAST_SEG jz dma_mid_sg;
-		if ((ahc->flags & AHC_TARGETMODE) != 0) {
+		if ((ahc->flags & AHC_TARGETROLE) != 0) {
 			test	SSTAT0, TARGET jz dma_last_sg;
 			if ((ahc->flags & AHC_TMODE_WIDEODD_BUG) != 0) {
 				test	DMAPARAMS, DIRECTION jz dma_mid_sg;
@@ -1080,7 +1085,7 @@ sg_load_done:
 		test	HCNT[0], 0x1 jz . + 2;
 		xor	DATA_COUNT_ODD, 0x1;
 
-		if ((ahc->flags & AHC_TARGETMODE) != 0) {
+		if ((ahc->flags & AHC_TARGETROLE) != 0) {
 			test	SSTAT0, TARGET jnz data_phase_loop;
 		}
 	}
@@ -1092,10 +1097,10 @@ data_phase_finish:
 	 * all other adapters, we'll loop after each S/G element
 	 * is loaded as well as if there is an overrun.
 	 */
-	if ((ahc->flags & AHC_TARGETMODE) != 0) {
+	if ((ahc->flags & AHC_TARGETROLE) != 0) {
 		test	SSTAT0, TARGET jnz data_phase_done;
 	}
-	if ((ahc->flags & AHC_INITIATORMODE) != 0) {
+	if ((ahc->flags & AHC_INITIATORROLE) != 0) {
 		test	SSTAT1, REQINIT jz .;
 		test	SSTAT1,PHASEMIS	jz data_phase_loop;
 	
@@ -1104,15 +1109,6 @@ data_phase_finish:
 			clr	CCSGCTL;
 			test	CCSGCTL, CCSGEN jnz .;
 		}
-
-		/*
-		 * Turn off BITBUCKET mode and notify the host
-		 * in the event of an overrun.
-		 */
-		test	SXFRCTL1,BITBUCKET jz data_phase_done;
-		and	SXFRCTL1, ~BITBUCKET;
-		mvi	INTSTAT,DATA_OVERRUN;
-		jmp	ITloop;
 	}
 
 data_phase_done:
@@ -1163,7 +1159,7 @@ bmov_resid:
 		or	SXFRCTL0, CLRSTCNT|CLRCHN;
 	}
 
-	if ((ahc->flags & AHC_TARGETMODE) != 0) {
+	if ((ahc->flags & AHC_TARGETROLE) != 0) {
 		test	SEQ_FLAGS, DPHASE_PENDING jz ITloop;
 		and	SEQ_FLAGS, ~DPHASE_PENDING;
 		/*
@@ -1177,7 +1173,7 @@ bmov_resid:
 		jmp	ITloop;
 	}
 
-if ((ahc->flags & AHC_INITIATORMODE) != 0) {
+if ((ahc->flags & AHC_INITIATORROLE) != 0) {
 /*
  * Command phase.  Set up the DMA registers and let 'er rip.
  */
@@ -1208,8 +1204,8 @@ p_command_from_host:
 			bmov	HCNT, STCNT, 3;
 		} else {
 			mvi	DINDEX, HADDR;
-			mvi	SCB_CDB_PTR	call bcopy_5;
-			call	clear_hcnt;
+			mvi	SCB_CDB_PTR call bcopy_4;
+			mov	SCB_CDB_LEN call set_hcnt;
 		}
 		mvi	DFCNTRL, (SCSIEN|SDMAEN|HDMAEN|DIRECTION|FIFORESET);
 	}
@@ -1261,6 +1257,10 @@ p_command_loop:
 	test	SCSISIGI, ACKI jnz .;
 	and	DFCNTRL, ~(SCSIEN|SDMAEN|HDMAEN);
 	test	DFCNTRL, (SCSIEN|SDMAEN|HDMAEN) jnz .;
+	if ((ahc->features & AHC_ULTRA2) != 0) {
+		/* Drop any residual from the S/G Preload queue */
+		or	SXFRCTL0, CLRSTCNT;
+	}
 	jmp	ITloop;
 
 /*
@@ -1413,14 +1413,9 @@ mesgin_complete:
  * process this information.  In the case of a non zero status byte, we 
  * additionally interrupt the kernel driver synchronously, allowing it to
  * decide if sense should be retrieved.  If the kernel driver wishes to request
- * sense, it will fill the kernel SCB with a request sense command and set
- * RETURN_1 to SEND_SENSE.  If RETURN_1 is set to SEND_SENSE we redownload
- * the SCB, and process it as the next command by adding it to the waiting list.
- * If the kernel driver does not wish to request sense, it need only clear
- * RETURN_1, and the command is allowed to complete normally.  We don't bother
- * to post to the QOUTFIFO in the error cases since it would require extra
- * work in the kernel driver to ensure that the entry was removed before the
- * command complete code tried processing it.
+ * sense, it will fill the kernel SCB with a request sense command, requeue
+ * it to the QINFIFO and tell us not to post to the QOUTFIFO by setting 
+ * RETURN_1 to SEND_SENSE.
  */
 
 /*
@@ -1437,23 +1432,10 @@ upload_scb:
 	mov	SCB_TAG		call dma_scb;
 	test	SCB_SCSI_STATUS, 0xff	jz complete;	/* Just a residual? */
 	mvi	INTSTAT, BAD_STATUS;			/* let driver know */
-	/*
-	 * Prepare to DMA this SCB in case we are told to retrieve sense.
-	 * Fills a delay slot after the INTSTAT as well.
-	 */
-	mvi	DMAPARAMS, HDMAEN|DIRECTION|FIFORESET;
+	nop;
 	cmp	RETURN_1, SEND_SENSE	jne complete;
-	mov	SCB_TAG		call dma_scb;
-add_to_waiting_list:
-	mov	SCB_NEXT,WAITING_SCBH;
-	mov	WAITING_SCBH, SCBPTR;
-	/*
-	 * Prepare our selection hardware before the busfree so we have a
-	 * high probability of winning arbitration.
-	 */
-	call	start_selection;
+	call	add_scb_to_free_list;
 	jmp	await_busfree;
-
 complete:
 	mov	SCB_TAG call complete_post;
 	jmp	await_busfree;
@@ -1475,7 +1457,7 @@ complete_post:
 	}
 	mvi	INTSTAT,CMDCMPLT ret;
 
-if ((ahc->flags & AHC_INITIATORMODE) != 0) {
+if ((ahc->flags & AHC_INITIATORROLE) != 0) {
 /*
  * Is it a disconnect message?  Set a flag in the SCB to remind us
  * and await the bus going free.  If this is an untagged transaction
@@ -1490,8 +1472,7 @@ mesgin_disconnect:
 	test	SCB_CONTROL, TAG_ENB jnz await_busfree;
 	mov	ARG_1, SCB_TAG;
 	mov	SAVED_LUN, SCB_LUN;
-	mov	SCB_SCSIID	call index_busy_target;
-	mov	DINDIR, ARG_1;
+	mov	SCB_SCSIID	call set_busy_target;
 	jmp	await_busfree;
 
 /*
@@ -1538,15 +1519,15 @@ mesgin_rdptrs:
  * Index into our Busy Target table.  SINDEX and DINDEX are modified
  * upon return.  SCBPTR may be modified by this action.
  */
-index_busy_target:
-	shr	SINDEX, 4;
+set_busy_target:
+	shr	DINDEX, 4, SINDEX;
 	if ((ahc->features & AHC_SCB_BTT) != 0) {
 		mov	SCBPTR, SAVED_LUN;
-		add	SINDEX, SCB_64_BTT;
+		add	DINDEX, SCB_64_BTT;
 	} else {
-		add	SINDEX, BUSY_TARGETS;
+		add	DINDEX, BUSY_TARGETS;
 	}
-	mov	DINDEX, SINDEX ret;
+	mov	DINDIR, ARG_1 ret;
 
 /*
  * Identify message?  For a reconnecting target, this tells us the lun
@@ -1562,13 +1543,28 @@ mesgin_identify:
 	 * for this target or the transaction is for a different lun, then
 	 * this must be an untagged transaction.
 	 */
-	mov	SAVED_SCSIID	call	index_busy_target;
-	mov	A, SINDIR;
-	cmp	A, SCB_LIST_NULL	je snoop_tag;
+fetch_busy_target:
+	shr	A, 4, SAVED_SCSIID;
+	if ((ahc->features & AHC_SCB_BTT) != 0) {
+		add	SINDEX, SCB_64_BTT, A;
+		mov	SCBPTR, SAVED_LUN;
+	} else {
+		add	SINDEX, BUSY_TARGETS, A;
+		if ((ahc->flags & AHC_SEQUENCER_DEBUG) != 0) {
+			add	A, -BUSY_TARGETS, SINDEX;
+			jc	. + 2;
+			mvi	INTSTAT, OUT_OF_RANGE;
+			add	A, -(BUSY_TARGETS + 16), SINDEX;
+			jnc	. + 2;
+			mvi	INTSTAT, OUT_OF_RANGE;
+		}
+	}
+	mov	ARG_1, SINDIR;
+	cmp	ARG_1, SCB_LIST_NULL	je snoop_tag;
 	if ((ahc->flags & AHC_PAGESCBS) != 0) {
-		mov	A	call findSCB;
+		mov	RETURN_1 call findSCB;
 	} else {
-		mov	SCBPTR, A;
+		mov	SCBPTR, RETURN_1;
 	}
 	if ((ahc->features & AHC_SCB_BTT) != 0) {
 		jmp setup_SCB_id_lun_okay;
@@ -1576,6 +1572,9 @@ mesgin_identify:
 		mov	A, SCB_LUN;
 		cmp	SAVED_LUN, A		je setup_SCB_id_lun_okay;
 	}
+	if ((ahc->flags & AHC_PAGESCBS) != 0) {
+		call	add_scb_to_disc_list;
+	}
 
 /*
  * Here we "snoop" the bus looking for a SIMPLE QUEUE TAG message.
@@ -1587,16 +1586,22 @@ mesgin_identify:
  */
 snoop_tag:
 	mov	NONE,SCSIDATL;		/* ACK Identify MSG */
-snoop_tag_loop:
 	call	phase_lock;
+	if ((ahc->flags & AHC_SEQUENCER_DEBUG) != 0) {
+		or	SEQ_FLAGS, 0x1;
+	}
 	cmp	LASTPHASE, P_MESGIN	jne not_found;
+	if ((ahc->flags & AHC_SEQUENCER_DEBUG) != 0) {
+		or	SEQ_FLAGS, 0x2;
+	}
 	cmp	SCSIBUSL,MSG_SIMPLE_Q_TAG jne not_found;
 get_tag:
 	if ((ahc->flags & AHC_PAGESCBS) != 0) {
 		mvi	ARG_1	call inb_next;	/* tag value */
 		mov	ARG_1	call findSCB;
 	} else {
-		mvi	SCBPTR	call inb_next;	/* tag value */
+		mvi	ARG_1	call inb_next;	/* tag value */
+		mov	SCBPTR, ARG_1;
 	}
 
 /*
@@ -1605,20 +1610,26 @@ get_tag:
  */
 setup_SCB:
 	mov	A, SAVED_SCSIID;
-	cmp	SCB_SCSIID, A	jne not_found;
+	if ((ahc->flags & AHC_SEQUENCER_DEBUG) != 0) {
+		or	SEQ_FLAGS, 0x4;
+	}
+	cmp	SCB_SCSIID, A	jne not_found_cleanup_scb;
 	mov	A, SAVED_LUN;
-	cmp	SCB_LUN, A	jne not_found;
+	if ((ahc->flags & AHC_SEQUENCER_DEBUG) != 0) {
+		or	SEQ_FLAGS, 0x8;
+	}
+	cmp	SCB_LUN, A	jne not_found_cleanup_scb;
 setup_SCB_id_lun_okay:
-	test	SCB_CONTROL,DISCONNECTED jz not_found;
-	if ((ahc->flags & AHC_PAGESCBS) != 0) {
-		mov	SCBPTR	call	rem_scb_from_disc_list;
+	if ((ahc->flags & AHC_SEQUENCER_DEBUG) != 0) {
+		or	SEQ_FLAGS, 0x10;
 	}
+	test	SCB_CONTROL,DISCONNECTED jz not_found_cleanup_scb;
 	and	SCB_CONTROL,~DISCONNECTED;
-	or	SEQ_FLAGS,IDENTIFY_SEEN;	/* make note of IDENTIFY */
+	mvi	SEQ_FLAGS,IDENTIFY_SEEN;	/* make note of IDENTIFY */
 	test	SCB_CONTROL, TAG_ENB	jnz setup_SCB_tagged;
 	mov	A, SCBPTR;
-	mov	SAVED_SCSIID	call	index_busy_target;
-	mvi	DINDIR, SCB_LIST_NULL;
+	mvi	ARG_1, SCB_LIST_NULL;
+	mov	SAVED_SCSIID	call	set_busy_target;
 	mov	SCBPTR, A;
 setup_SCB_tagged:
 	call	set_transfer_settings;
@@ -1627,6 +1638,10 @@ setup_SCB_tagged:
 	mvi	HOST_MSG	call mk_mesg;
 	jmp	mesgin_done;
 
+not_found_cleanup_scb:
+	if ((ahc->flags & AHC_PAGESCBS) != 0) {
+		call	add_scb_to_free_list;
+	}
 not_found:
 	mvi	INTSTAT, NO_MATCH;
 	jmp	mesgin_done;
@@ -1673,7 +1688,7 @@ inb_last:
 	mov	NONE,SCSIDATL ret;		/*dummy read from latch to ACK*/
 }
 
-if ((ahc->flags & AHC_TARGETMODE) != 0) {
+if ((ahc->flags & AHC_TARGETROLE) != 0) {
 /*
  * Change to a new phase.  If we are changing the state of the I/O signal,
  * from out to in, wait an additional data release delay before continuing.
@@ -1732,47 +1747,35 @@ assert:
  */
 if ((ahc->flags & AHC_PAGESCBS) != 0) {
 findSCB:
-	mov	SCBPTR, DISCONNECTED_SCBH;	/* Initialize SCBPTR */
 	mov	A, SINDEX;			/* Tag passed in SINDEX */
-	mvi	RETURN_2, SCB_LIST_NULL;	/* Head of list */
+	cmp	DISCONNECTED_SCBH, SCB_LIST_NULL je findSCB_notFound;
+	mov	SCBPTR, DISCONNECTED_SCBH;	/* Initialize SCBPTR */
+	mvi	ARG_2, SCB_LIST_NULL;		/* Head of list */
 	jmp	findSCB_loop;
 findSCB_next:
-	mov	RETURN_2, SCBPTR;
 	cmp	SCB_NEXT, SCB_LIST_NULL je findSCB_notFound;
+	mov	ARG_2, SCBPTR;
 	mov	SCBPTR,SCB_NEXT;
 findSCB_loop:
 	cmp	SCB_TAG, A	jne findSCB_next;
-	mov	SINDEX, SCBPTR 	ret;
-findSCB_notFound:
-	/*
-	 * We didn't find it.  Page in the SCB and make it look
-	 * like it was at the head of the appropriate scb list.
-	 */
-	mov	ARG_1, A; /* Save tag */
-	mov	ALLZEROS call get_free_or_disc_scb;
-	mvi	DMAPARAMS, HDMAEN|DIRECTION|FIFORESET;
-	mov	ARG_1	call dma_scb;
-	mvi	RETURN_2, SCB_LIST_NULL;	/* Head of list */
-	/* Jump instead of call as we want to return anyway */
-	test	SCB_CONTROL, DISCONNECTED jnz add_scb_to_disc_list;
-	jmp	add_scb_to_free_list;
-}
-
-/*
- * This routine expects SINDEX to contain the index of the SCB to be
- * removed, SCBPTR to be pointing to that SCB, and ARG_2 to be the
- * SCBID of the SCB just previous to this one in the list or SCB_LIST_NULL
- * if it is at the head.
- */
 rem_scb_from_disc_list:
-/* Remove this SCB from the disconnection list */
 	cmp	ARG_2, SCB_LIST_NULL	je rHead;
 	mov	DINDEX, SCB_NEXT;
+	mov	SINDEX, SCBPTR;
 	mov	SCBPTR, ARG_2;
 	mov	SCB_NEXT, DINDEX;
 	mov	SCBPTR, SINDEX ret;
 rHead:
 	mov	DISCONNECTED_SCBH,SCB_NEXT ret;
+findSCB_notFound:
+	/*
+	 * We didn't find it.  Page in the SCB.
+	 */
+	mov	ARG_1, A; /* Save tag */
+	mov	ALLZEROS call get_free_or_disc_scb;
+	mvi	DMAPARAMS, HDMAEN|DIRECTION|FIFORESET;
+	mov	ARG_1	jmp dma_scb;
+}
 
 /*
  * Prepare the hardware to post a byte to host memory given an
@@ -1845,7 +1848,7 @@ bcopy_3:
 	mov	DINDIR, SINDIR ret;
 }
 
-if ((ahc->flags & AHC_TARGETMODE) != 0) {
+if ((ahc->flags & AHC_TARGETROLE) != 0) {
 /*
  * Setup addr assuming that A is an index into
  * an array of 32byte objects, SINDEX contains
@@ -2049,12 +2052,13 @@ get_free_or_disc_scb:
 	cmp	FREE_SCBH, SCB_LIST_NULL jne dequeue_free_scb;
 	cmp	DISCONNECTED_SCBH, SCB_LIST_NULL jne dequeue_disc_scb;
 return_error:
+	mvi	INTSTAT, NO_FREE_SCB;
 	mvi	SINDEX, SCB_LIST_NULL	ret;
 dequeue_disc_scb:
 	mov	SCBPTR, DISCONNECTED_SCBH;
 dma_up_scb:
 	mvi	DMAPARAMS, FIFORESET;
-	mov	SCB_TAG		call dma_scb;
+	mov	SCB_TAG	call dma_scb;
 unlink_disc_scb:
 	mov	DISCONNECTED_SCBH, SCB_NEXT ret;
 dequeue_free_scb:
@@ -2067,8 +2071,10 @@ add_scb_to_disc_list:
  * candidates for paging out an SCB if one is needed for a new command.
  * Modifying the disconnected list is a critical(pause dissabled) section.
  */
+BEGIN_CRITICAL
 	mov	SCB_NEXT, DISCONNECTED_SCBH;
 	mov	DISCONNECTED_SCBH, SCBPTR ret;
+END_CRITICAL
 }
 return:
 	ret;