aic79xx.seq

linux 内核源代码

scbdma_idle:
	/*
	 * Don't bother downloading new SCBs to execute
	 * if select-outs are currently frozen or we have
	 * a MK_MESSAGE SCB waiting to enter the queue.
	 */
	test	SEQ_FLAGS2, SELECTOUT_QFROZEN|PENDING_MK_MESSAGE
		jnz scbdma_no_new_scbs;
BEGIN_CRITICAL;
	test	QOFF_CTLSTA, NEW_SCB_AVAIL jnz fetch_new_scb;
scbdma_no_new_scbs:
	cmp	COMPLETE_DMA_SCB_HEAD[1], SCB_LIST_NULL jne dma_complete_scb;
	cmp	COMPLETE_SCB_HEAD[1], SCB_LIST_NULL je return;
	/* FALLTHROUGH */
fill_qoutfifo:
	/*
	 * Keep track of the SCBs we are dmaing just
	 * in case the DMA fails or is aborted.
	 */
	bmov	COMPLETE_SCB_DMAINPROG_HEAD, COMPLETE_SCB_HEAD, 2;
	mvi	CCSCBCTL, CCSCBRESET;
	bmov	SCBHADDR, QOUTFIFO_NEXT_ADDR, 4;
	mov	A, QOUTFIFO_NEXT_ADDR;
	bmov	SCBPTR, COMPLETE_SCB_HEAD, 2;
fill_qoutfifo_loop:
	bmov	CCSCBRAM, SCBPTR, 2;
	mov	CCSCBRAM, SCB_SGPTR[0];
	mov	CCSCBRAM, QOUTFIFO_ENTRY_VALID_TAG;
	mov	NONE, SDSCB_QOFF;
	inc	INT_COALESCING_CMDCOUNT;
	add	CMDS_PENDING, -1;
	adc	CMDS_PENDING[1], -1;
	cmp	SCB_NEXT_COMPLETE[1], SCB_LIST_NULL je fill_qoutfifo_done;
	cmp	CCSCBADDR, CCSCBADDR_MAX je fill_qoutfifo_done;
	test	QOFF_CTLSTA, SDSCB_ROLLOVR jnz fill_qoutfifo_done;
	/*
	 * Don't cross an ADB or Cachline boundary when DMA'ing
	 * completion entries.  In PCI mode, at least in 32/33
	 * configurations, the SCB DMA engine may lose its place
	 * in the data-stream should the target force a retry on
	 * something other than an 8byte aligned boundary. In
	 * PCI-X mode, we do this to avoid split transactions since
	 * many chipsets seem to be unable to format proper split
	 * completions to continue the data transfer.
	 */
	add	SINDEX, A, CCSCBADDR;
	test	SINDEX, CACHELINE_MASK jz fill_qoutfifo_done;
	bmov	SCBPTR, SCB_NEXT_COMPLETE, 2;
	jmp	fill_qoutfifo_loop;
fill_qoutfifo_done:
	mov	SCBHCNT, CCSCBADDR;
	mvi	CCSCBCTL, CCSCBEN|CCSCBRESET;
	bmov	COMPLETE_SCB_HEAD, SCB_NEXT_COMPLETE, 2;
	mvi	SCB_NEXT_COMPLETE[1], SCB_LIST_NULL ret;

fetch_new_scb:
	bmov	SCBHADDR, NEXT_QUEUED_SCB_ADDR, 4;
	mvi	CCARREN|CCSCBEN|CCSCBDIR|CCSCBRESET jmp dma_scb;
dma_complete_scb:
	bmov	SCBPTR, COMPLETE_DMA_SCB_HEAD, 2;
	bmov	SCBHADDR, SCB_BUSADDR, 4;
	mvi	CCARREN|CCSCBEN|CCSCBRESET jmp dma_scb;

/*
 * Either post or fetch an SCB from host memory.  The caller
 * is responsible for polling for transfer completion.
 *
 * Prerequisits: Mode == M_CCHAN
 *		 SINDEX contains CCSCBCTL flags
 *		 SCBHADDR set to Host SCB address
 *		 SCBPTR set to SCB src location on "push" operations
 */
SET_SRC_MODE	M_CCHAN;
SET_DST_MODE	M_CCHAN;
dma_scb:
	mvi	SCBHCNT, SCB_TRANSFER_SIZE;
	mov	CCSCBCTL, SINDEX ret;

setjmp:
	/*
	 * At least on the A, a return in the same
	 * instruction as the bmov results in a return
	 * to the caller, not to the new address at the
	 * top of the stack.  Since we want the latter
	 * (we use setjmp to register a handler from an
	 * interrupt context but not invoke that handler
	 * until we return to our idle loop), use a
	 * separate ret instruction.
	 */
	bmov	LONGJMP_ADDR, STACK, 2;
	ret;
setjmp_inline:
	bmov	LONGJMP_ADDR, STACK, 2;
longjmp:
	bmov	STACK, LONGJMP_ADDR, 2 ret;
END_CRITICAL;

/*************************** Chip Bug Work Arounds ****************************/
/*
 * Must disable interrupts when setting the mode pointer
 * register as an interrupt occurring mid update will
 * fail to store the new mode value for restoration on
 * an iret.
 */
if ((ahd->bugs & AHD_SET_MODE_BUG) != 0) {
set_mode_work_around:
	mvi	SEQINTCTL, INTVEC1DSL;
	mov	MODE_PTR, SINDEX;
	clr	SEQINTCTL ret;
}


if ((ahd->bugs & AHD_INTCOLLISION_BUG) != 0) {
set_seqint_work_around:
	mov	SEQINTCODE, SINDEX;
	mvi	SEQINTCODE, NO_SEQINT ret;
}

/************************ Packetized LongJmp Routines *************************/
SET_SRC_MODE	M_SCSI;
SET_DST_MODE	M_SCSI;
start_selection:
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_FAINT_LED_BUG) != 0) {
		/*
		 * On Rev A. hardware, the busy LED is only
		 * turned on automaically during selections
		 * and re-selections.  Make the LED status
		 * more useful by forcing it to be on from
		 * the point of selection until our idle
		 * loop determines that neither of our FIFOs
		 * are busy.  This handles the non-packetized
		 * case nicely as we will not return to the
		 * idle loop until the busfree at the end of
		 * each transaction.
		 */
		or	SBLKCTL, DIAGLEDEN|DIAGLEDON;
	}
	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;
	if ((ahd->bugs & AHD_FAINT_LED_BUG) != 0) {
		/*
		 * On Rev A. hardware, the busy LED is only
		 * turned on automaically during selections
		 * and re-selections.  Make the LED status
		 * more useful by forcing it to be on from
		 * the point of re-selection until our idle
		 * loop determines that neither of our FIFOs
		 * are busy.  This handles the non-packetized
		 * case nicely as we will not return to the
		 * idle loop until the busfree at the end of
		 * each transaction.
		 */
		or	SBLKCTL, DIAGLEDEN|DIAGLEDON;
	}
	/* 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;
	}

	/*
	 * The whole list made it.  Clear our tail pointer to indicate
	 * that the per-target selection queue is now empty.
	 */
	cmp	SCB_NEXT[1], SCB_LIST_NULL je select_out_clear_tail;

	/*
	 * Requeue any SCBs not sent, to the tail of the waiting Q.
	 * We know that neither the per-TID list nor the list of
	 * TIDs is empty.  Use this knowledge to our advantage and
	 * queue the remainder to the tail of the global execution
	 * queue.
	 */
	bmov	REG0, SCB_NEXT, 2;
select_out_queue_remainder:
	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_clear_tail:
	/*
	 * Queue any pending MK_MESSAGE SCB for this target now
	 * that the queue is empty.
	 */
	test	SEQ_FLAGS2, PENDING_MK_MESSAGE jz select_out_no_mk_message_scb;
	mov	A, MK_MESSAGE_SCSIID;
	cmp	SCB_SCSIID, A jne select_out_no_mk_message_scb;
	and	SEQ_FLAGS2, ~PENDING_MK_MESSAGE;
	bmov	REG0, MK_MESSAGE_SCB, 2;
	jmp select_out_queue_remainder;

select_out_no_mk_message_scb:
	/*
	 * Clear this target's execution tail and increment the queue.
	 */
	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_mode_cleared;
	test	LQOSTAT1, LQOPHACHGINPKT jnz unexpected_nonpkt_mode_cleared;

	/*
	 * 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;