aic7xxx.seq

基于组件方式开发操作系统的OSKIT源代码

/*
 * Adaptec 274x/284x/294x device driver firmware for Linux and FreeBSD.
 *
 * Copyright (c) 1994-1999 Justin Gibbs.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification, immediately at the beginning of the file.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * Where this Software is combined with software released under the terms of 
 * the GNU Public License (GPL) and the terms of the GPL would require the 
 * combined work to also be released under the terms of the GPL, the terms
 * and conditions of this License will apply in addition to those of the
 * GPL with the exception of any terms or conditions of this License that
 * conflict with, or are expressly prohibited by, the GPL.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	$Id: aic7xxx.seq,v 1.84.2.4 1999/05/16 00:08:46 gibbs Exp $
 */

#include <dev/aic7xxx/aic7xxx.reg>
#include <cam/scsi/scsi_message.h>

/*
 * A few words on the waiting SCB list:
 * After starting the selection hardware, we check for reconnecting targets
 * as well as for our selection to complete just in case the reselection wins
 * bus arbitration.  The problem with this is that we must keep track of the
 * SCB that we've already pulled from the QINFIFO and started the selection
 * on just in case the reselection wins so that we can retry the selection at
 * a later time.  This problem cannot be resolved by holding a single entry
 * in scratch ram since a reconnecting target can request sense and this will
 * create yet another SCB waiting for selection.  The solution used here is to 
 * use byte 27 of the SCB as a psuedo-next pointer and to thread a list
 * of SCBs that are awaiting selection.  Since 0-0xfe are valid SCB indexes, 
 * SCB_LIST_NULL is 0xff which is out of range.  An entry is also added to
 * this list everytime a request sense occurs or after completing a non-tagged
 * command for which a second SCB has been queued.  The sequencer will
 * automatically consume the entries.
 */

reset:
	clr	SCSISIGO;		/* De-assert BSY */
	and	SXFRCTL1, ~BITBUCKET;
	/* Always allow reselection */
	and	SCSISEQ, ENSELI|ENRSELI|ENAUTOATNP, SCSISEQ_TEMPLATE;

	if ((ahc->features & AHC_CMD_CHAN) != 0) {
		/* Ensure that no DMA operations are in progress */
		clr	CCSGCTL;
		clr	CCSCBCTL;
	}

poll_for_work:
	call	clear_target_state;
	and	SXFRCTL0, ~SPIOEN;
	if ((ahc->features & AHC_QUEUE_REGS) == 0) {
		mov	A, QINPOS;
	}
poll_for_work_loop:
	if ((ahc->features & AHC_QUEUE_REGS) == 0) {
		and	SEQCTL, ~PAUSEDIS;
	}
	test	SSTAT0, SELDO|SELDI	jnz selection;
	test	SCSISEQ, ENSELO	jnz poll_for_work;
	if ((ahc->features & AHC_TWIN) != 0) {
		/*
		 * Twin channel devices cannot handle things like SELTO
		 * interrupts on the "background" channel.  So, if we
		 * are selecting, keep polling the current channel util
		 * either a selection or reselection occurs.
		 */
		xor	SBLKCTL,SELBUSB;	/* Toggle to the other bus */
		test	SSTAT0, SELDO|SELDI	jnz selection;
		test	SCSISEQ, ENSELO	jnz poll_for_work;
		xor	SBLKCTL,SELBUSB;	/* Toggle back */
	}
	cmp	WAITING_SCBH,SCB_LIST_NULL jne start_waiting;
test_queue:
	/* Has the driver posted any work for us? */
	if ((ahc->features & AHC_QUEUE_REGS) != 0) {
		test	QOFF_CTLSTA, SCB_AVAIL jz poll_for_work_loop;
		mov	NONE, SNSCB_QOFF;
		inc	QINPOS;
	} else {
		or	SEQCTL, PAUSEDIS;
		cmp	KERNEL_QINPOS, A je poll_for_work_loop;
		inc	QINPOS;
		and	SEQCTL, ~PAUSEDIS;
	}

/*
 * We have at least one queued SCB now and we don't have any 
 * SCBs in the list of SCBs awaiting selection.  If we have
 * any SCBs available for use, pull the tag from the QINFIFO
 * and get to work on it.
 */
	if ((ahc->flags & AHC_PAGESCBS) != 0) {
		mov	ALLZEROS	call	get_free_or_disc_scb;
	}

dequeue_scb:
	add	A, -1, QINPOS;
	mvi	QINFIFO_OFFSET call fetch_byte;

	if ((ahc->flags & AHC_PAGESCBS) == 0) {
		/* In the non-paging case, the SCBID == hardware SCB index */
		mov	SCBPTR, RETURN_2;
	}
dma_queued_scb:
/*
 * DMA the SCB from host ram into the current SCB location.
 */
	mvi	DMAPARAMS, HDMAEN|DIRECTION|FIFORESET;
	mov	RETURN_2	 call dma_scb;

/*
 * Preset the residual fields in case we never go through a data phase.
 * This isn't done by the host so we can avoid a DMA to clear these
 * fields for the normal case of I/O that completes without underrun
 * or overrun conditions.
 */
	if ((ahc->features & AHC_CMD_CHAN) != 0) {
		bmov	SCB_RESID_DCNT, SCB_DATACNT, 3;
	} else {
		mov	SCB_RESID_DCNT[0],SCB_DATACNT[0];
		mov	SCB_RESID_DCNT[1],SCB_DATACNT[1];
		mov	SCB_RESID_DCNT[2],SCB_DATACNT[2];
	}
	mov	SCB_RESID_SGCNT, SCB_SGCOUNT;

start_scb:
	/*
	 * Place us on the waiting list in case our selection
	 * doesn't win during bus arbitration.
	 */
	mov	SCB_NEXT,WAITING_SCBH;
	mov	WAITING_SCBH, SCBPTR;
start_waiting:
	/*
	 * Pull the first entry off of the waiting SCB list.
	 */
	mov	SCBPTR, WAITING_SCBH;
	call	start_selection;
	jmp	poll_for_work;

start_selection:
	if ((ahc->features & AHC_TWIN) != 0) {
		and	SINDEX,~SELBUSB,SBLKCTL;/* Clear channel select bit */
		and	A,SELBUSB,SCB_TCL;	/* Get new channel bit */
		or	SINDEX,A;
		mov	SBLKCTL,SINDEX;		/* select channel */
	}
initialize_scsiid:
	mov	SINDEX, SCSISEQ_TEMPLATE;
	if ((ahc->flags & AHC_TARGETMODE) != 0) {
		test	SCB_CONTROL, TARGET_SCB jz . + 4;
		if ((ahc->features & AHC_ULTRA2) != 0) {
			mov	SCSIID_ULTRA2, SCB_CMDPTR[2];
		} else {
			mov	SCSIID, SCB_CMDPTR[2];
		}
		or	SINDEX, TEMODE;
		jmp	initialize_scsiid_fini;
	}
	if ((ahc->features & AHC_ULTRA2) != 0) {
		and	A, TID, SCB_TCL;	/* Get target ID */
		and	SCSIID_ULTRA2, OID;	/* Clear old target */
		or	SCSIID_ULTRA2, A;
	} else {
		and	A, TID, SCB_TCL;	/* Get target ID */
		and	SCSIID, OID;		/* Clear old target */
		or	SCSIID, A;
	}
initialize_scsiid_fini:
	mov	SCSISEQ, SINDEX ret;

/*
 * Initialize transfer settings and clear the SCSI channel.
 * SINDEX should contain any additional bit's the client wants
 * set in SXFRCTL0.  We also assume that the current SCB is
 * a valid SCB for the target we wish to talk to.
 */
initialize_channel:
	or	SXFRCTL0, CLRSTCNT|CLRCHN, SINDEX;
set_transfer_settings:
	if ((ahc->features & AHC_ULTRA) != 0) {
		test	SCB_CONTROL, ULTRAENB jz . + 2;
		or	SXFRCTL0, FAST20;
	} 
/*
 * Initialize SCSIRATE with the appropriate value for this target.
 */
	if ((ahc->features & AHC_ULTRA2) != 0) {
		bmov	SCSIRATE, SCB_SCSIRATE, 2 ret;
	} else {
		mov	SCSIRATE, SCB_SCSIRATE ret;
	}

selection:
	test	SSTAT0,SELDO	jnz select_out;
	mvi	CLRSINT0, CLRSELDI;
select_in:
	if ((ahc->flags & AHC_TARGETMODE) != 0) {
		if ((ahc->flags & AHC_INITIATORMODE) != 0) {
			test	SSTAT0, TARGET	jz initiator_reselect;
		}

		/*
		 * We've just been selected.  Assert BSY and
		 * setup the phase for receiving messages
		 * from the target.
		 */
		mvi	SCSISIGO, P_MESGOUT|BSYO;
		mvi	CLRSINT1, CLRBUSFREE;

		/*
		 * Setup the DMA for sending the identify and
		 * command information.
		 */
		or	SEQ_FLAGS, CMDPHASE_PENDING;

		mov     A, TQINPOS;
		if ((ahc->features & AHC_CMD_CHAN) != 0) {
			mvi	DINDEX, CCHADDR;
			mvi	TMODE_CMDADDR call set_32byte_addr;
			mvi	CCSCBCTL, CCSCBRESET;
		} else {
			mvi	DINDEX, HADDR;
			mvi	TMODE_CMDADDR call set_32byte_addr;
			mvi	DFCNTRL, FIFORESET;
		}

		/* Initiator that selected us */
		and	SAVED_TCL, SELID_MASK, SELID;
		if ((ahc->features & AHC_CMD_CHAN) != 0) {
			mov	CCSCBRAM, SAVED_TCL;
		} else {
			mov	DFDAT, SAVED_TCL;
		}

		/* The Target ID we were selected at */
		if ((ahc->features & AHC_CMD_CHAN) != 0) {
			if ((ahc->features & AHC_MULTI_TID) != 0) {
				and	CCSCBRAM, OID, TARGIDIN;
			} else if ((ahc->features & AHC_ULTRA2) != 0) {
				and	CCSCBRAM, OID, SCSIID_ULTRA2;
			} else {
				and	CCSCBRAM, OID, SCSIID;
			}
		} else {
			if ((ahc->features & AHC_MULTI_TID) != 0) {
				and	DFDAT, OID, TARGIDIN;
			} else if ((ahc->features & AHC_ULTRA2) != 0) {
				and	DFDAT, OID, SCSIID_ULTRA2;
			} else {
				and	DFDAT, OID, SCSIID;
			}
		}

		/* No tag yet */
		mvi	INITIATOR_TAG, SCB_LIST_NULL;

		/*
		 * If ATN isn't asserted, the target isn't interested
		 * in talking to us.  Go directly to bus free.
		 */
		test	SCSISIGI, ATNI	jz	target_busfree;

		/*
		 * Watch ATN closely now as we pull in messages from the
		 * initiator.  We follow the guidlines from section 6.5
		 * of the SCSI-2 spec for what messages are allowed when.
		 */
		call	target_inb;

		/*
		 * Our first message must be one of IDENTIFY, ABORT, or
		 * BUS_DEVICE_RESET.
		 */
		/* XXX May need to be more lax here for older initiators... */
		test	DINDEX, MSG_IDENTIFYFLAG jz host_target_message_loop;
		/* Store for host */
		if ((ahc->features & AHC_CMD_CHAN) != 0) {
			mov	CCSCBRAM, DINDEX;
		} else {
			mov	DFDAT, DINDEX;
		}

		/* Remember for disconnection decision */
		test	DINDEX, MSG_IDENTIFY_DISCFLAG jnz . + 2;
		/* XXX Honor per target settings too */
		or	SEQ_FLAGS, NO_DISCONNECT;

		test	SCSISIGI, ATNI	jz	ident_messages_done;
		call	target_inb;
		/*
		 * If this is a tagged request, the tagged message must
		 * immediately follow the identify.  We test for a valid
		 * tag message by seeing if it is >= MSG_SIMPLE_Q_TAG and
		 * < MSG_IGN_WIDE_RESIDUE.
		 */
		add	A, -MSG_SIMPLE_Q_TAG, DINDEX;
		jnc	ident_messages_done;
		add	A, -MSG_IGN_WIDE_RESIDUE, DINDEX;
		jc	ident_messages_done;
		/* Store for host */
		if ((ahc->features & AHC_CMD_CHAN) != 0) {
			mov	CCSCBRAM, DINDEX;
		} else {
			mov	DFDAT, DINDEX;
		}
		
		/*
		 * If the initiator doesn't feel like providing a tag number,
		 * we've got a failed selection and must transition to bus
		 * free.
		 */
		test	SCSISIGI, ATNI	jz	target_busfree;

		/*
		 * Store the tag for the host.
		 */
		call	target_inb;
		if ((ahc->features & AHC_CMD_CHAN) != 0) {
			mov	CCSCBRAM, DINDEX;
		} else {
			mov	DFDAT, DINDEX;
		}
		mov	INITIATOR_TAG, DINDEX;
		jmp	ident_messages_done;

		/*
		 * Pushed message loop to allow the kernel to
		 * run it's own target mode message state engine.
		 */
host_target_message_loop:
		mvi	INTSTAT, HOST_MSG_LOOP;
		nop;
		cmp	RETURN_1, EXIT_MSG_LOOP	je target_ITloop;
		test	SSTAT0, SPIORDY jz .;
		jmp	host_target_message_loop;

ident_messages_done:
		/* If ring buffer is full, return busy or queue full */
		mov	A, KERNEL_TQINPOS;
		cmp	TQINPOS, A jne tqinfifo_has_space;
		mvi	P_STATUS|BSYO call change_phase;
		cmp	INITIATOR_TAG, SCB_LIST_NULL je . + 3;
		mvi	STATUS_QUEUE_FULL call target_outb;
		jmp	target_busfree_wait;
		mvi	STATUS_BUSY call target_outb;
		jmp	target_busfree_wait;
tqinfifo_has_space:	
		/* Terminate the ident list */
		if ((ahc->features & AHC_CMD_CHAN) != 0) {
			mvi	CCSCBRAM, SCB_LIST_NULL;
		} else {
			mvi	DFDAT, SCB_LIST_NULL;
		}
		or	SEQ_FLAGS, TARG_CMD_PENDING|IDENTIFY_SEEN;
		test	SCSISIGI, ATNI	jnz target_mesgout_pending_msg;
		jmp	target_ITloop;
		
/*
 * We carefully toggle SPIOEN to allow us to return the 
 * message byte we receive so it can be checked prior to
 * driving REQ on the bus for the next byte.
 */
target_inb:
		/*
		 * Drive REQ on the bus by enabling SCSI PIO.
		 */
		or	SXFRCTL0, SPIOEN;
		/* Wait for the byte */
		test	SSTAT0, SPIORDY jz .;
		/* Prevent our read from triggering another REQ */
		and	SXFRCTL0, ~SPIOEN;
		/* Save latched contents */
		mov	DINDEX, SCSIDATL ret;
	}

if ((ahc->flags & AHC_INITIATORMODE) != 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.
 */
initiator_reselect:
	/* XXX test for and handle ONE BIT condition */
	and	SAVED_TCL, SELID_MASK, SELID;
	if ((ahc->features & AHC_TWIN) != 0) {
		test	SBLKCTL, SELBUSB	jz . + 2;
		or	SAVED_TCL, SELBUSB;
	}
	or	SXFRCTL0, SPIOEN|CLRSTCNT|CLRCHN;
	mvi	CLRSINT1,CLRBUSFREE;
	or	SIMODE1, ENBUSFREE;		/*
						 * We aren't expecting a
						 * bus free, so interrupt
						 * the kernel driver if it
						 * happens.
						 */
	mvi	MSG_OUT, MSG_NOOP;		/* No message to send */
	jmp	ITloop;
}

/*
 * After the selection, remove this SCB from the "waiting SCB"
 * list.  This is achieved by simply moving our "next" pointer into
 * WAITING_SCBH.  Our next pointer will be set to null the next time this
 * SCB is used, so don't bother with it now.
 */
select_out:
	/* Turn off the selection hardware */
	and	SCSISEQ, ENSELI|ENRSELI|ENAUTOATNP, SCSISEQ_TEMPLATE;
	mvi	CLRSINT0, CLRSELDO;
	mov	SCBPTR, WAITING_SCBH;
	mov	WAITING_SCBH,SCB_NEXT;
	mov	SAVED_TCL, SCB_TCL;
	if ((ahc->flags & AHC_TARGETMODE) != 0) {
		test	SSTAT0, TARGET	jz initiator_select;

		/*
		 * We've just re-selected an initiator.
		 * Assert BSY and setup the phase for
		 * sending our identify messages.
		 */
		mvi	P_MESGIN|BSYO call change_phase;
		mvi	CLRSINT1,CLRBUSFREE;

		/*
		 * Start out with a simple identify message.
		 */
		and	A, LID, SCB_TCL;
		or	A, MSG_IDENTIFYFLAG call target_outb;