aic7xxx.seq

基于组件方式开发操作系统的OSKIT源代码

data_phase_loop:
/* Guard against overruns */
	test	SG_COUNT, 0xff jnz 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.
 */
	or	SXFRCTL1,BITBUCKET;
	and	DMAPARAMS, ~(HDMAEN|SDMAEN);
	if ((p->features & AHC_CMD_CHAN) != 0) {
		if ((p->features & AHC_ULTRA2) != 0) {
			bmov	HCNT, ALLONES, 3;
		}
		bmov	STCNT, ALLONES, 3;
	} else {
		mvi	STCNT[0], 0xFF;
		mvi	STCNT[1], 0xFF;
		mvi	STCNT[2], 0xFF;
	}
data_phase_inbounds:
/* If we are the last SG block, tell the hardware. */
if ((p->features & AHC_ULTRA2) == 0) {
	cmp	SG_COUNT,0x01 jne data_phase_wideodd;
	and	DMAPARAMS, ~WIDEODD;
}
data_phase_wideodd:
	if ((p->features & AHC_ULTRA2) != 0) {
		mov	SINDEX, ALLONES;
		mov	DFCNTRL, DMAPARAMS;
		test	SSTAT0, SDONE jnz .;
data_phase_dma_loop:
		test	SSTAT0, SDONE jnz data_phase_dma_done;
		test	SSTAT1,PHASEMIS	jz data_phase_dma_loop;	/* ie. underrun */
data_phase_dma_phasemis:
		test	SSTAT0,SDONE	jnz . + 2;
		clr	SINDEX;			/* Remember the phasemiss */
	} else {
		mov	DMAPARAMS  call dma;
	}

data_phase_dma_done:
/* Go tell the host about any overruns */
	test	SXFRCTL1,BITBUCKET jnz data_phase_overrun;

/* Exit if we had an underrun.  dma clears SINDEX in this case. */
	test	SINDEX,0xff	jz data_phase_finish;

/*
 * Advance the scatter-gather pointers if needed 
 */
sg_advance:
	dec	SG_COUNT;	/* one less segment to go */

	test	SG_COUNT, 0xff	jz data_phase_finish; /* Are we done? */
/*
 * Load a struct scatter and set up the data address and length.
 * If the working value of the SG count is nonzero, then
 * we need to load a new set of values.
 *
 * This, like all DMA's, assumes little-endian host data storage.
 */
sg_load:
	if ((p->features & AHC_CMD_CHAN) != 0) {
		/*
		 * Do we have any prefetch left???
		 */
		cmp	CCSGADDR, CCSGADDR_MAX jne prefetched_segs_avail;

		/*
		 * Fetch MIN(CCSGADDR_MAX, (SG_COUNT * 8)) bytes.
		 */
		add	A, -(CCSGRAM_MAXSEGS + 1), SG_COUNT;
		mvi	A, CCSGADDR_MAX;
		jc	. + 2;
		shl	A, 3, SG_COUNT;
		mov	CCHCNT, A;
		bmov	CCHADDR, SG_NEXT, 4;
		mvi	CCSGCTL, CCSGEN|CCSGRESET;
		test	CCSGCTL, CCSGDONE jz .;
		and	CCSGCTL, ~CCSGEN;
		test	CCSGCTL, CCSGEN jnz .;
		mvi	CCSGCTL, CCSGRESET;
prefetched_segs_avail:
		bmov 	HADDR, CCSGRAM, 8;
		if ((p->features & AHC_ULTRA2) == 0) {
			bmov    STCNT, HCNT, 3;
		}
	} else {
		mvi	DINDEX, HADDR;
		mvi	SG_NEXT	call bcopy_4;

		mvi	HCNT[0],SG_SIZEOF;
		clr	HCNT[1];
		clr	HCNT[2];

		or	DFCNTRL, HDMAEN|DIRECTION|FIFORESET;

		call	dma_finish;

		/*
		 * Copy data from FIFO into SCB data pointer and data count.
		 * This assumes that the SG segments are of the form:
		 * struct ahc_dma_seg {
		 *	u_int32_t	addr;	four bytes, little-endian order
		 *	u_int32_t	len;	four bytes, little endian order
		 * };
		 */
		mvi	HADDR	call dfdat_in_7;
		call	set_stcnt_from_hcnt;
	}

/* Advance the SG pointer */
	clr	A;			/* add sizeof(struct scatter) */
	add	SG_NEXT[0],SG_SIZEOF;
	adc	SG_NEXT[1],A;

	test    SSTAT1, REQINIT jz .;
	test	SSTAT1,PHASEMIS	jz data_phase_loop;

	if ((p->features & AHC_ULTRA2) != 0) {
		mov	DFCNTRL, DMAPARAMS;
		test	SSTAT0, SDONE jnz .;
	}

data_phase_finish:
/*
 * After a DMA finishes, save the SG and STCNT residuals back into the SCB
 * We use STCNT instead of HCNT, since it's a reflection of how many bytes 
 * were transferred on the SCSI (as opposed to the host) bus.
 */
	if ((p->features & AHC_ULTRA2) != 0) {
		call	ultra2_dmafinish;
	}
	if ((p->features & AHC_ULTRA2) == 0) {
		if ((p->features & AHC_CMD_CHAN) != 0) {
			bmov    SCB_RESID_DCNT, STCNT, 3;
			mov	SCB_RESID_SGCNT, SG_COUNT;
		} else {
			mov	SCB_RESID_DCNT[0],STCNT[0];
			mov	SCB_RESID_DCNT[1],STCNT[1];
			mov	SCB_RESID_DCNT[2],STCNT[2];
			mov	SCB_RESID_SGCNT, SG_COUNT;
		}
	}

	jmp	ITloop;

data_phase_overrun:
	if ((p->features & AHC_ULTRA2) != 0) {
		call	ultra2_dmafinish;
	}
/*
 * Turn off BITBUCKET mode and notify the host
 */
	and	SXFRCTL1, ~BITBUCKET;
	mvi	INTSTAT,DATA_OVERRUN;
	jmp	ITloop;

ultra2_dmafinish:
	if ((p->features & AHC_ULTRA2) != 0) {
		test	DFCNTRL, DIRECTION jnz ultra2_dmahalt;
		and	DFCNTRL, ~SCSIEN;
		test	DFCNTRL, SCSIEN jnz .;
		or	DFCNTRL, FIFOFLUSH;
		test	DFSTATUS, FIFOEMP jz . - 1;
ultra2_dmahalt:
		and     DFCNTRL, ~(SCSIEN|HDMAEN);
		test	DFCNTRL, HDMAEN jnz .;
		bmov	SCB_RESID_DCNT, STCNT, 3;
		mov	SCB_RESID_SGCNT, SG_COUNT;
		or	SXFRCTL0, CLRSTCNT|CLRCHN;
		ret;
	}

/*
 * Command phase.  Set up the DMA registers and let 'er rip.
 */
p_command:
	call	assert;

/*
 * Load HADDR and HCNT.
 */
	if ((p->features & AHC_CMD_CHAN) != 0) {
		bmov	HADDR, SCB_CMDPTR, 5;
		bmov	HCNT[1], ALLZEROS, 2;
		if ((p->features & AHC_ULTRA2) == 0) {
			bmov	STCNT, HCNT, 3;
		}
	} else {
		mvi	DINDEX, HADDR;
		mvi	SCB_CMDPTR	call bcopy_5;
		clr	HCNT[1];
		clr	HCNT[2];
		call	set_stcnt_from_hcnt;
	}

	if ((p->features & AHC_ULTRA2) == 0) {
		mvi	(SCSIEN|SDMAEN|HDMAEN|DIRECTION|FIFORESET) call dma;
	} else {
		mvi	DFCNTRL, (PRELOADEN|SCSIEN|HDMAEN|DIRECTION);
		test	SSTAT0, SDONE jnz .;
p_command_dma_loop:
		test	SSTAT0, DMADONE jnz p_command_ultra2_dma_done;
		test	SSTAT1,PHASEMIS	jz p_command_dma_loop;	/* ie. underrun */
p_command_ultra2_dma_done:
		and     DFCNTRL, ~(SCSIEN|HDMAEN);
		test	DFCNTRL, HDMAEN jnz .;
		or	SXFRCTL0, CLRSTCNT|CLRCHN;
	}
	jmp	ITloop;

/*
 * Status phase.  Wait for the data byte to appear, then read it
 * and store it into the SCB.
 */
p_status:
	call	assert;

	mov	SCB_TARGET_STATUS, SCSIDATL;
	jmp	ITloop;

/*
 * Message out phase.  If MSG_OUT is 0x80, build I full indentify message
 * sequence and send it to the target.  In addition, if the MK_MESSAGE bit
 * is set in the SCB_CONTROL byte, interrupt the host and allow it to send
 * it's own message.
 * 
 * If MSG_OUT is == HOST_MSG, also interrupt the host and take a message.
 * This is done to allow the hsot 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:
	or      SCSISIGO,ATNO,LASTPHASE;/* turn on ATN for the retry */
p_mesgout:
	mov	SINDEX, MSG_OUT;
	cmp	SINDEX, MSG_IDENTIFYFLAG jne p_mesgout_from_host;
p_mesgout_identify:
	if ((p->features & AHC_WIDE) != 0) {
		and	SINDEX,0xf,SCB_TCL;	/* lun */
	} else {
		and	SINDEX,0x7,SCB_TCL;	/* lun */
	}
	and	A,DISCENB,SCB_CONTROL;	/* mask off disconnect privledge */
	or	SINDEX,A;		/* or in disconnect privledge */
	or	SINDEX,MSG_IDENTIFYFLAG;
p_mesgout_mk_message:
	test	SCB_CONTROL,MK_MESSAGE  jz p_mesgout_tag;
	mov	SCSIDATL, SINDEX;	/* Send the last byte */
	jmp	p_mesgout_from_host + 1;/* Skip HOST_MSG test */
/*
 * Send a tag message if TAG_ENB is set in the SCB control block.
 * Use SCB_TAG (the position in the kernel's SCB array) as the tag value.
 */
p_mesgout_tag:
	test	SCB_CONTROL,TAG_ENB jz  p_mesgout_onebyte;
	mov	SCSIDATL, SINDEX;	/* Send the identify message */
	call	phase_lock;
	cmp	LASTPHASE, P_MESGOUT	jne p_mesgout_done;
	and	SCSIDATL,TAG_ENB|SCB_TAG_TYPE,SCB_CONTROL;
	call	phase_lock;
	cmp	LASTPHASE, P_MESGOUT	jne p_mesgout_done;
	mov	SCB_TAG	jmp p_mesgout_onebyte;
/*
 * Interrupt the driver, and allow it to send a message
 * if it asks.
 */
p_mesgout_from_host:
	cmp	SINDEX, HOST_MSG	jne p_mesgout_onebyte;
	mvi     INTSTAT,AWAITING_MSG;
	nop;
	/*
	 * Did the host detect a phase change?
	 */
	cmp	RETURN_1, MSGOUT_PHASEMIS je p_mesgout_done;

p_mesgout_onebyte:
	mvi	CLRSINT1, CLRATNO;
	mov	SCSIDATL, SINDEX;

/*
 * If the next bus phase after ATN drops is a message out, it means
 * that the target is requesting that the last message(s) be resent.
 */
	call	phase_lock;
	cmp     LASTPHASE, P_MESGOUT    je p_mesgout_retry;

p_mesgout_done:
	mvi	CLRSINT1,CLRATNO;	/* Be sure to turn ATNO off */
	mov	LAST_MSG, MSG_OUT;
	cmp	MSG_OUT, MSG_IDENTIFYFLAG jne . + 2;
	and	SCB_CONTROL, ~MK_MESSAGE;
	mvi	MSG_OUT, MSG_NOOP;	/* No message left */
	jmp	ITloop;

/*
 * Message in phase.  Bytes are read using Automatic PIO mode.
 */
p_mesgin:
	mvi	ACCUM		call inb_first;	/* read the 1st message byte */

	test	A,MSG_IDENTIFYFLAG	jnz mesgin_identify;
	cmp	A,MSG_DISCONNECT	je mesgin_disconnect;
	cmp	A,MSG_SAVEDATAPOINTER	je mesgin_sdptrs;
	cmp	ALLZEROS,A		je mesgin_complete;
	cmp	A,MSG_RESTOREPOINTERS	je mesgin_rdptrs;
	cmp	A,MSG_EXTENDED		je mesgin_extended;
	cmp	A,MSG_MESSAGE_REJECT	je mesgin_reject;
	cmp	A,MSG_NOOP		je mesgin_done;

rej_mesgin:
/*
 * We have no idea what this message in is, so we issue a message reject
 * and hope for the best.  In any case, rejection should be a rare
 * occurrence - signal the driver when it happens.
 */
	mvi	INTSTAT,SEND_REJECT;		/* let driver know */

	mvi	MSG_MESSAGE_REJECT	call mk_mesg;

mesgin_done:
	mov	NONE,SCSIDATL;		/*dummy read from latch to ACK*/
	jmp	ITloop;


mesgin_complete:
/*
 * We got a "command complete" message, so put the SCB_TAG into the QOUTFIFO,
 * and trigger a completion interrupt.  Before doing so, check to see if there
 * is a residual or the status byte is something other than STATUS_GOOD (0).
 * In either of these conditions, we upload the SCB back to the host so it can
 * 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.
 */

/*
 * First check for residuals
 */
	test	SCB_RESID_SGCNT,0xff	jnz upload_scb;
	test	SCB_TARGET_STATUS,0xff	jz complete;	/* Good Status? */
upload_scb:
	mvi	DMAPARAMS, FIFORESET;
	mov	SCB_TAG		call dma_scb;
check_status:
	test	SCB_TARGET_STATUS,0xff	jz complete;	/* Just a residual? */
	mvi	INTSTAT,BAD_STATUS;			/* let driver know */
	nop;
	cmp	RETURN_1, SEND_SENSE	jne complete;
	/* This SCB becomes the next to execute as it will retrieve sense */
	mvi	DMAPARAMS, HDMAEN|DIRECTION|FIFORESET;
	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;
	jmp	await_busfree;

complete:
	/* If we are untagged, clear our address up in host ram */
	test	SCB_CONTROL, TAG_ENB jnz complete_post;
	mov	A, SAVED_TCL;
	mvi	UNTAGGEDSCB_OFFSET call post_byte_setup;
	mvi	SCB_LIST_NULL call post_byte;

complete_post:
	/* Post the SCB and issue an interrupt */
	if ((p->features & AHC_QUEUE_REGS) != 0) {
		mov	A, SDSCB_QOFF;
	} else {
		mov	A, QOUTPOS;
	}
	mvi	QOUTFIFO_OFFSET call post_byte_setup;
	mov	SCB_TAG call post_byte;
	if ((p->features & AHC_QUEUE_REGS) == 0) {
		inc 	QOUTPOS;
	}
	mvi	INTSTAT,CMDCMPLT;

add_to_free_list:
	call	add_scb_to_free_list;
	jmp	await_busfree;

/*
 * Is it an extended message?  Copy the message to our message buffer and
 * notify the host.  The host will tell us whether to reject this message,
 * respond to it with the message that the host placed in our message buffer,
 * or simply to do nothing.
 */
mesgin_extended:
	mvi	INTSTAT,EXTENDED_MSG;		/* let driver know */
	jmp	ITloop;

/*
 * Is it a disconnect message?  Set a flag in the SCB to remind us
 * and await the bus going free.
 */
mesgin_disconnect:
	or	SCB_CONTROL,DISCONNECTED;
	call	add_scb_to_disc_list;
	jmp	await_busfree;

/*
 * Save data pointers message:
 * Copying RAM values back to SCB, for Save Data Pointers message, but
 * only if we've actually been into a data phase to change them.  This
 * protects against bogus data in scratch ram and the residual counts
 * since they are only initialized when we go into data_in or data_out.
 */
mesgin_sdptrs:
	test	SEQ_FLAGS, DPHASE	jz mesgin_done;
	/*
	 * The SCB SGPTR becomes the next one we'll download,
	 * and the SCB DATAPTR becomes the current SHADDR.
	 * Use the residual number since STCNT is corrupted by
	 * any message transfer.
	 */
	if ((p->features & AHC_CMD_CHAN) != 0) {
		bmov    SCB_SGCOUNT, SG_COUNT, 5;
		bmov    SCB_DATAPTR, SHADDR, 4;
		bmov    SCB_DATACNT, SCB_RESID_DCNT, 3;
	} else {
		mvi	DINDEX, SCB_SGCOUNT;
		mvi	SG_COUNT	call bcopy_5;
		mvi	DINDEX, SCB_DATAPTR;
		mvi	SHADDR		call bcopy_4;
		mvi	SCB_RESID_DCNT	call	bcopy_3;
	}
	jmp	mesgin_done;

/*
 * Restore pointers message?  Data pointers are recopied from the
 * SCB anytime we enter a data phase for the first time, so all
 * we need to do is clear the DPHASE flag and let the data phase
 * code do the rest.
 */
mesgin_rdptrs:
	and	SEQ_FLAGS, ~DPHASE;		/*
						 * We'll reload them
						 * the next time through
						 * the dataphase.
						 */
	jmp	mesgin_done;

/*
 * Identify message?  For a reconnecting target, this tells us the lun
 * that the reconnection is for - find the correct SCB and switch to it,
 * clearing the "disconnected" bit so we don't "find" it by accident later.
 */
mesgin_identify:
	
	if ((p->features & AHC_WIDE) != 0) {
		and	A,0x0f;		/* lun in lower four bits */
	} else {
		and	A,0x07;		/* lun in lower three bits */
	}
	or      SAVED_TCL,A;		/* SAVED_TCL should be complete now */

	mvi     ARG_2, SCB_LIST_NULL;   /* SCBID of prev SCB in disc List */
	call	get_untagged_SCBID;
	cmp	ARG_1, SCB_LIST_NULL	je snoop_tag;
	if ((p->flags & AHC_PAGESCBS) != 0) {
		test	SEQ_FLAGS, SCBPTR_VALID	jz use_retrieveSCB;
	}
	/*
	 * If the SCB was found in the disconnected list (as is
	 * always the case in non-paging scenarios), SCBPTR is already
	 * set to the correct SCB.  So, simply setup the SCB and get
	 * on with things.
	 */