aic79xx.seq

linux-2.6.15.6

BEGIN_CRITICAL;
	if ((ahd->bugs & AHD_SENT_SCB_UPDATE_BUG) != 0) {
		/*
		 * Razor #494
		 * Rev A hardware fails to update LAST/CURR/NEXTSCB
		 * correctly after a packetized selection in several
		 * situations:
		 *
		 * 1) If only one command existed in the queue, the
		 *    LAST/CURR/NEXTSCB are unchanged.
		 *
		 * 2) In a non QAS, protocol allowed phase change,
		 *    the queue is shifted 1 too far.  LASTSCB is
		 *    the last SCB that was correctly processed.
		 * 
		 * 3) In the QAS case, if the full list of commands
		 *    was successfully sent, NEXTSCB is NULL and neither
		 *    CURRSCB nor LASTSCB can be trusted.  We must
		 *    manually walk the list counting MAXCMDCNT elements
		 *    to find the last SCB that was sent correctly.
		 *
		 * To simplify the workaround for this bug in SELDO
		 * handling, we initialize LASTSCB prior to enabling
		 * selection so we can rely on it even for case #1 above.
		 */
		bmov	LASTSCB, WAITING_TID_HEAD, 2;
	}
	bmov	CURRSCB, WAITING_TID_HEAD, 2;
	bmov	SCBPTR, WAITING_TID_HEAD, 2;
	shr	SELOID, 4, SCB_SCSIID;
	/*
	 * If we want to send a message to the device, ensure
	 * we are selecting with atn irregardless of our packetized
	 * agreement.  Since SPI4 only allows target reset or PPR
	 * messages if this is a packetized connection, the change
	 * to our negotiation table entry for this selection will
	 * be cleared when the message is acted on.
	 */
	test	SCB_CONTROL, MK_MESSAGE jz . + 3;
	mov	NEGOADDR, SELOID;
	or	NEGCONOPTS, ENAUTOATNO;
	or	SCSISEQ0, ENSELO ret;
END_CRITICAL;

/*
 * Allocate a FIFO for a non-packetized transaction.
 * In RevA hardware, both FIFOs must be free before we
 * can allocate a FIFO for a non-packetized transaction.
 */
allocate_fifo_loop:
	/*
	 * Do whatever work is required to free a FIFO.
	 */
	call	idle_loop_service_fifos;
	SET_MODE(M_SCSI, M_SCSI)
allocate_fifo:
	if ((ahd->bugs & AHD_NONPACKFIFO_BUG) != 0) {
		and	A, FIFO0FREE|FIFO1FREE, DFFSTAT;
		cmp	A, FIFO0FREE|FIFO1FREE jne allocate_fifo_loop;
	} else {
		test	DFFSTAT, FIFO1FREE jnz allocate_fifo1;
		test	DFFSTAT, FIFO0FREE jz allocate_fifo_loop;
		mvi	DFFSTAT, B_CURRFIFO_0;
		SET_MODE(M_DFF0, M_DFF0)
		bmov	SCBPTR, ALLOCFIFO_SCBPTR, 2 ret;
	}
SET_SRC_MODE	M_SCSI;
SET_DST_MODE	M_SCSI;
allocate_fifo1:
	mvi	DFFSTAT, CURRFIFO_1;
	SET_MODE(M_DFF1, M_DFF1)
	bmov	SCBPTR, ALLOCFIFO_SCBPTR, 2 ret;

/*
 * We have been reselected as an initiator
 * or selected as a target.
 */
SET_SRC_MODE	M_SCSI;
SET_DST_MODE	M_SCSI;
select_in:
	if ((ahd->bugs & AHD_BUSFREEREV_BUG) != 0) {
		/*
		 * Test to ensure that the bus has not
		 * already gone free prior to clearing
		 * any stale busfree status.  This avoids
		 * a window whereby a busfree just after
		 * a selection could be missed.
		 */
		test	SCSISIGI, BSYI jz . + 2;
		mvi	CLRSINT1,CLRBUSFREE;
		or	SIMODE1, ENBUSFREE;
	}
	or	SXFRCTL0, SPIOEN;
	and	SAVED_SCSIID, SELID_MASK, SELID;
	and	A, OID, IOWNID;
	or	SAVED_SCSIID, A;
	mvi	CLRSINT0, CLRSELDI;
	jmp	ITloop;

/*
 * We have successfully selected out.
 *
 * Clear SELDO.
 * Dequeue all SCBs sent from the waiting queue
 * Requeue all SCBs *not* sent to the tail of the waiting queue
 * Take Razor #494 into account for above.
 *
 * In Packetized Mode:
 *	Return to the idle loop.  Our interrupt handler will take
 *	care of any incoming L_Qs.
 *
 * In Non-Packetize Mode:
 *	Continue to our normal state machine.
 */
SET_SRC_MODE	M_SCSI;
SET_DST_MODE	M_SCSI;
select_out:
BEGIN_CRITICAL;
	/* Clear out all SCBs that have been successfully sent. */
	if ((ahd->bugs & AHD_SENT_SCB_UPDATE_BUG) != 0) {
		/*
		 * For packetized, the LQO manager clears ENSELO on
		 * the assertion of SELDO.  If we are non-packetized,
		 * LASTSCB and CURRSCB are accurate.
		 */
		test	SCSISEQ0, ENSELO jnz use_lastscb;

		/*
		 * The update is correct for LQOSTAT1 errors.  All
		 * but LQOBUSFREE are handled by kernel interrupts.
		 * If we see LQOBUSFREE, return to the idle loop.
		 * Once we are out of the select_out critical section,
		 * the kernel will cleanup the LQOBUSFREE and we will
		 * eventually restart the selection if appropriate.
		 */
		test	LQOSTAT1, LQOBUSFREE jnz idle_loop;

		/*
		 * On a phase change oustside of packet boundaries,
		 * LASTSCB points to the currently active SCB context
		 * on the bus.
		 */
		test	LQOSTAT2, LQOPHACHGOUTPKT jnz use_lastscb;

		/*
		 * If the hardware has traversed the whole list, NEXTSCB
		 * will be NULL, CURRSCB and LASTSCB cannot be trusted,
		 * but MAXCMDCNT is accurate.  If we stop part way through
		 * the list or only had one command to issue, NEXTSCB[1] is
		 * not NULL and LASTSCB is the last command to go out.
		 */
		cmp	NEXTSCB[1], SCB_LIST_NULL jne use_lastscb;

		/*
		 * Brute force walk.
		 */
		bmov	SCBPTR, WAITING_TID_HEAD, 2;
		mvi	SEQINTCTL, INTVEC1DSL;
		mvi	MODE_PTR, MK_MODE(M_CFG, M_CFG);
		mov	A, MAXCMDCNT;
		mvi	MODE_PTR, MK_MODE(M_SCSI, M_SCSI);
		clr	SEQINTCTL;
find_lastscb_loop:
		dec	A;
		test	A, 0xFF jz found_last_sent_scb;
		bmov	SCBPTR, SCB_NEXT, 2;
		jmp	find_lastscb_loop;
use_lastscb:
		bmov	SCBPTR, LASTSCB, 2;
found_last_sent_scb:
		bmov	CURRSCB, SCBPTR, 2;
curscb_ww_done:
	} else {
		bmov	SCBPTR, CURRSCB, 2;
	}

	/*
	 * Requeue any SCBs not sent, to the tail of the waiting Q.
	 */
	cmp	SCB_NEXT[1], SCB_LIST_NULL je select_out_list_done;

	/*
	 * We know that neither the per-TID list nor the list of
	 * TIDs is empty.  Use this knowledge to our advantage.
	 */
	bmov	REG0, SCB_NEXT, 2;
	bmov	SCBPTR, WAITING_TID_TAIL, 2;
	bmov	SCB_NEXT2, REG0, 2;
	bmov	WAITING_TID_TAIL, REG0, 2;
	jmp	select_out_inc_tid_q;

select_out_list_done:
	/*
	 * The whole list made it.  Just clear our TID's tail pointer
	 * unless we were queued independently due to our need to
	 * send a message.
	 */
	test	SCB_CONTROL, MK_MESSAGE jnz select_out_inc_tid_q;
	shr	DINDEX, 3, SCB_SCSIID;
	or	DINDEX, 1;	/* Want only the second byte */
	mvi	DINDEX[1], ((WAITING_SCB_TAILS) >> 8);
	mvi	DINDIR, SCB_LIST_NULL;
select_out_inc_tid_q:
	bmov	SCBPTR, WAITING_TID_HEAD, 2;
	bmov	WAITING_TID_HEAD, SCB_NEXT2, 2;
	cmp	WAITING_TID_HEAD[1], SCB_LIST_NULL jne . + 2;
	mvi	WAITING_TID_TAIL[1], SCB_LIST_NULL;
	bmov	SCBPTR, CURRSCB, 2;
	mvi	CLRSINT0, CLRSELDO;
	test	LQOSTAT2, LQOPHACHGOUTPKT jnz unexpected_nonpkt_phase;
	test	LQOSTAT1, LQOPHACHGINPKT jnz unexpected_nonpkt_phase;

	/*
	 * If this is a packetized connection, return to our
	 * idle_loop and let our interrupt handler deal with
	 * any connection setup/teardown issues.  The only
	 * exceptions are the case of MK_MESSAGE and task management
	 * SCBs.
	 */
	if ((ahd->bugs & AHD_LQO_ATNO_BUG) != 0) {
		/*
		 * In the A, the LQO manager transitions to LQOSTOP0 even if
		 * we have selected out with ATN asserted and the target
		 * REQs in a non-packet phase.
		 */
		test 	SCB_CONTROL, MK_MESSAGE jz select_out_no_message;
		test	SCSISIGO, ATNO jnz select_out_non_packetized;
select_out_no_message:
	}
	test	LQOSTAT2, LQOSTOP0 jz select_out_non_packetized;
	test	SCB_TASK_MANAGEMENT, 0xFF jz idle_loop;
	SET_SEQINTCODE(TASKMGMT_FUNC_COMPLETE)
	jmp	idle_loop;

select_out_non_packetized:
	/* Non packetized request. */
	and     SCSISEQ0, ~ENSELO;
	if ((ahd->bugs & AHD_BUSFREEREV_BUG) != 0) {
		/*
		 * Test to ensure that the bus has not
		 * already gone free prior to clearing
		 * any stale busfree status.  This avoids
		 * a window whereby a busfree just after
		 * a selection could be missed.
		 */
		test	SCSISIGI, BSYI jz . + 2;
		mvi	CLRSINT1,CLRBUSFREE;
		or	SIMODE1, ENBUSFREE;
	}
	mov	SAVED_SCSIID, SCB_SCSIID;
	mov	SAVED_LUN, SCB_LUN;
	mvi	SEQ_FLAGS, NO_CDB_SENT;
END_CRITICAL;
	or	SXFRCTL0, SPIOEN;

	/*
	 * As soon as we get a successful selection, the target
	 * should go into the message out phase since we have ATN
	 * asserted.
	 */
	mvi	MSG_OUT, MSG_IDENTIFYFLAG;

	/*
	 * Main loop for information transfer phases.  Wait for the
	 * target to assert REQ before checking MSG, C/D and I/O for
	 * the bus phase.
	 */
mesgin_phasemis:
ITloop:
	call	phase_lock;

	mov	A, LASTPHASE;

	test	A, ~P_DATAIN_DT	jz p_data;
	cmp	A,P_COMMAND	je p_command;
	cmp	A,P_MESGOUT	je p_mesgout;
	cmp	A,P_STATUS	je p_status;
	cmp	A,P_MESGIN	je p_mesgin;

	SET_SEQINTCODE(BAD_PHASE)
	jmp	ITloop;			/* Try reading the bus again. */

/*
 * Command phase.  Set up the DMA registers and let 'er rip.
 */
p_command:
	test	SEQ_FLAGS, NOT_IDENTIFIED jz p_command_okay;
	SET_SEQINTCODE(PROTO_VIOLATION)
p_command_okay:
	test	MODE_PTR, ~(MK_MODE(M_DFF1, M_DFF1))
		jnz p_command_allocate_fifo;
	/*
	 * Command retry.  Free our current FIFO and
	 * re-allocate a FIFO so transfer state is
	 * reset.
	 */
SET_SRC_MODE	M_DFF1;
SET_DST_MODE	M_DFF1;
	mvi	DFFSXFRCTL, RSTCHN|CLRSHCNT;
	SET_MODE(M_SCSI, M_SCSI)
p_command_allocate_fifo:
	bmov	ALLOCFIFO_SCBPTR, SCBPTR, 2;
	call	allocate_fifo;
SET_SRC_MODE	M_DFF1;
SET_DST_MODE	M_DFF1;
	add	NONE, -17, SCB_CDB_LEN;
	jnc	p_command_embedded;
p_command_from_host:
	bmov	HADDR[0], SCB_HOST_CDB_PTR, 9;
	mvi	SG_CACHE_PRE, LAST_SEG;
	mvi	DFCNTRL, (PRELOADEN|SCSIEN|HDMAEN);
	jmp	p_command_xfer;
p_command_embedded:
	bmov	SHCNT[0], SCB_CDB_LEN,  1;
	bmov	DFDAT, SCB_CDB_STORE, 16; 
	mvi	DFCNTRL, SCSIEN;
p_command_xfer:
	and	SEQ_FLAGS, ~NO_CDB_SENT;
	if ((ahd->features & AHD_FAST_CDB_DELIVERY) != 0) {
		/*
		 * To speed up CDB delivery in Rev B, all CDB acks
		 * are "released" to the output sync as soon as the
		 * command phase starts.  There is only one problem
		 * with this approach.  If the target changes phase
		 * before all data are sent, we have left over acks
		 * that can go out on the bus in a data phase.  Due
		 * to other chip contraints, this only happens if
		 * the target goes to data-in, but if the acks go
		 * out before we can test SDONE, we'll think that
		 * the transfer has completed successfully.  Work
		 * around this by taking advantage of the 400ns or
		 * 800ns dead time between command phase and the REQ
		 * of the new phase.  If the transfer has completed
		 * successfully, SCSIEN should fall *long* before we
		 * see a phase change.  We thus treat any phasemiss
		 * that occurs before SCSIEN falls as an incomplete
		 * transfer.
		 */
		test	SSTAT1, PHASEMIS jnz p_command_xfer_failed;
		test	DFCNTRL, SCSIEN jnz . - 1;
	} else {
		test	DFCNTRL, SCSIEN jnz .;
	}
	/*
	 * DMA Channel automatically disabled.
	 * Don't allow a data phase if the command
	 * was not fully transferred.
	 */
	test	SSTAT2, SDONE jnz ITloop;
p_command_xfer_failed:
	or	SEQ_FLAGS, NO_CDB_SENT;
	jmp	ITloop;


/*
 * Status phase.  Wait for the data byte to appear, then read it
 * and store it into the SCB.
 */
SET_SRC_MODE	M_SCSI;
SET_DST_MODE	M_SCSI;
p_status:
	test	SEQ_FLAGS,NOT_IDENTIFIED jnz mesgin_proto_violation;
p_status_okay:
	mov	SCB_SCSI_STATUS, SCSIDAT;
	or	SCB_CONTROL, STATUS_RCVD;
	jmp	ITloop;

/*
 * Message out phase.  If MSG_OUT is MSG_IDENTIFYFLAG, build a full
 * indentify message sequence and send it to the target.  The host may
 * override this behavior by setting the MK_MESSAGE bit in the SCB
 * control byte.  This will cause us to interrupt the host and allow
 * it to handle the message phase completely on its own.  If the bit
 * associated with this target is set, we will also interrupt the host,
 * thereby allowing it to send a message on the next selection regardless
 * of the transaction being sent.
 * 
 * If MSG_OUT is == HOST_MSG, also interrupt the host and take a message.
 * This is done to allow the host to send messages outside of an identify
 * sequence while protecting the seqencer from testing the MK_MESSAGE bit
 * on an SCB that might not be for the current nexus. (For example, a
 * BDR message in responce to a bad reselection would leave us pointed to
 * an SCB that doesn't have anything to do with the current target).
 *
 * Otherwise, treat MSG_OUT as a 1 byte message to send (abort, abort tag,
 * bus device reset).
 *
 * When there are no messages to send, MSG_OUT should be set to MSG_NOOP,
 * in case the target decides to put us in this phase for some strange
 * reason.
 */
p_mesgout_retry:
	/* Turn on ATN for the retry */
	mvi	SCSISIGO, ATNO;
p_mesgout:
	mov	SINDEX, MSG_OUT;
	cmp	SINDEX, MSG_IDENTIFYFLAG jne p_mesgout_from_host;
	test	SCB_CONTROL,MK_MESSAGE	jnz host_message_loop;
p_mesgout_identify:
	or	SINDEX, MSG_IDENTIFYFLAG|DISCENB, SCB_LUN;
	test	SCB_CONTROL, DISCENB jnz . + 2;
	and	SINDEX, ~DISCENB;
/*
 * Send a tag message if TAG_ENB is set in the SCB control block.
 * Use SCB_NONPACKET_TAG as the tag value.
 */
p_mesgout_tag:
	test	SCB_CONTROL,TAG_ENB jz  p_mesgout_onebyte;
	mov	SCSIDAT, SINDEX;	/* Send the identify message */
	call	phase_lock;
	cmp	LASTPHASE, P_MESGOUT	jne p_mesgout_done;
	and	SCSIDAT,TAG_ENB|SCB_TAG_TYPE,SCB_CONTROL;