Clear the SCSI channel after we go to busfree instead of after re/selection.

Only enable reselections once the channel and SCSIRATE have been cleared.

Add a pause block around the test busy code in the non-tagged case to simplify
error recovery in the corner case of aborting an SCB that just got started.

Simplify reselection processing by removing the call to initialize_scsiid.

Clear the scsiseq re/select control bits and setup for catching bogus
busfrees earlier in the re/select process.

Improve the automatic PIO code.  It turns out that SPIORDY is not a reliable
hardware condition bit, so use REQINIT intstead.  Don't rely on PHASEMIS
either since it can take too long to come true.  Use a brute force comparison
instead.

Remove some unnecessary overhead in the command complete processing.  It
should be nearly impossible to overflow the QOUTFIFO (worst case 9 command
have to complete with at least 6 of them requiring paging on an aic7850),
so don't take the additional PIO hit to guard against this condition.  If we
don't see our interrupt in time, the system has bigger problems elsewhere.
If this ever does happen, the timeout handler will notice and retry the
command.

2 files changed, 53 insertions, 46 deletions

diff --git a/sys/dev/aic7xxx/aic7xxx.seq b/sys/dev/aic7xxx/aic7xxx.seq
index 0193e3b..430bbb5 100644
--- a/sys/dev/aic7xxx/aic7xxx.seq
+++ b/sys/dev/aic7xxx/aic7xxx.seq
@@ -84,12 +84,13 @@ reset:
 	clr	SCSISIGO		/* De-assert BSY */
 
 p_busfree:
-	mvi	SCSISEQ,ENRSELI		/* Always allow reselection */
+	or	SXFRCTL0, CLRCHN
 	clr	SCSIRATE		/*
 					 * We don't know the target we will
 					 * connect to, so default to narrow
 					 * transfers to avoid parity problems.
 					 */
+	mvi	SCSISEQ,ENRSELI		/* Always allow reselection */
 	mvi	LASTPHASE, P_BUSFREE
 	and	FLAGS,0x07		/* clear target specific flags */
 poll_for_work:
@@ -153,6 +154,7 @@ test_busy:
 	test	SCB_CONTROL, TAG_ENB	jnz start_scb
 	mov	SAVED_SCBPTR, SCBPTR
 	mov	SCB_TCL		call	index_untagged_scb
+	mvi	SEQCTL,0x50			/* PAUSEDIS|FASTMODE */
 	mov	ARG_1, SINDIR			/*
 						 * ARG_1 should
 						 * now have the SCB ID of
@@ -172,8 +174,7 @@ test_busy:
 	mov	ALLZEROS	call findSCB
 	/*
 	 * If we couldn't find it, tell the kernel.  This should
-	 * only happen if the parent SCB was aborted and this
-	 * one was already here at the time of the abort.
+	 * never happen.
 	 */
 	cmp	SINDEX, SCB_LIST_NULL	jne paged_busy_link
 	mvi	INTSTAT, NO_MATCH_BUSY
@@ -182,12 +183,15 @@ paged_busy_link:
 	mov	SCB_LINKED_NEXT, CUR_SCBID 
 	/* Put it back on the disconnected list */
 	call	add_scb_to_disc_list
+	mvi	SEQCTL,0x10			/* FASTMODE */
 	jmp	poll_for_work
 simple_busy_link:
 	mov	SCBPTR, ARG_1
 	mov	SCB_LINKED_NEXT, CUR_SCBID 
+	mvi	SEQCTL,0x10			/* FASTMODE */
 	jmp	poll_for_work
 make_busy:
+	mvi	SEQCTL,0x10			/* FASTMODE */
 	mov	DINDIR, CUR_SCBID
 	mov	SCBPTR, SAVED_SCBPTR
 
@@ -259,7 +263,8 @@ wait_for_selection:
  */
 reselect:
 	clr	MSG_LEN		/* Don't have anything in the mesg buffer */
-	mov	SELID		call initialize_scsiid
+	/* XXX test for and handle ONE BIT condition */
+	and	SAVED_TCL, 0xf0, SELID
 	or	FLAGS,RESELECTED
 	jmp	select2
 
@@ -272,13 +277,26 @@ reselect:
 select:
 	mov	WAITING_SCBH,SCB_NEXT
 select2:
+	/* Turn off the selection hardware */
+	mvi	SCSISEQ,ENAUTOATNP		/*
+						 * ATN on parity errors
+						 * for "in" phases
+						 */
+	mvi	CLRSINT0,0x60			/* CLRSELDI|CLRSELDO */
+	mvi	CLRSINT1,CLRBUSFREE
+	or	SIMODE1, ENBUSFREE		/*
+						 * We aren't expecting a
+						 * bus free, so interrupt
+						 * the kernel driver if it
+						 * happens.
+						 */
 /*
  * Initialize SCSIRATE with the appropriate value for this target.
  * The SCSIRATE settings for each target are stored in an array
  * based at TARG_SCRATCH.
  */
 ndx_dtr:
-	shr	A,SCSIID,4
+	shr	A,SAVED_TCL,4
 	test	SBLKCTL,SELBUSB	jz ndx_dtr_2
 	or	SAVED_TCL, SELBUSB /* Add the channel bit while we're here */
 	or	A,0x08		/* Channel B entries add 8 */
@@ -291,18 +309,12 @@ ndx_dtr_2:
  */
 ultra:
 	and	DINDEX,0xdf,SXFRCTL0            /* default to Ultra disabled */
-	/*
-	 * Set CLRCHN here before the target has entered a data transfer mode -
-	 * with synchronous SCSI, if you do it later, you blow away some
-	 * data in the SCSI FIFO that the target has already sent to you.
-	 */
-	or	DINDEX, CLRCHN
 	mvi	SINDEX, ULTRA_ENB_B
-	test	SCSIID, 0x80     jnz ultra_2     /* Target ID > 7 */
+	test	SAVED_TCL, 0x80     jnz ultra_2     /* Target ID > 7 */
 	test	SBLKCTL, SELBUSB jnz ultra_2     /* Second channel device */
 	dec	SINDEX
 ultra_2:
-	mov     FUNCTION1,SCSIID 
+	mov     FUNCTION1,SAVED_TCL
 	mov     A,FUNCTION1
 	test	SINDIR, A	jz set_sxfrctl0
 	or	DINDEX, ULTRAEN
@@ -310,18 +322,6 @@ ultra_2:
 set_sxfrctl0:
 	mov	SXFRCTL0,DINDEX
 
-	mvi	SCSISEQ,ENAUTOATNP		/*
-						 * ATN on parity errors
-						 * for "in" phases
-						 */
-	mvi	CLRSINT1,CLRBUSFREE
-	mvi	CLRSINT0,0x60			/* CLRSELDI|CLRSELDO */
-	or	SIMODE1, ENBUSFREE		/*
-						 * We aren't expecting a
-						 * bus free, so interrupt
-						 * the kernel driver if it
-						 * happens.
-						 */
 /*
  * Main loop for information transfer phases.  If BSY is false, then
  * we have a bus free condition, expected or not.  Otherwise, wait
@@ -516,8 +516,8 @@ p_command:
 p_status:
 	call	assert
 
-	mvi	SCB_TARGET_STATUS	call inb_first
-	jmp	mesgin_done
+	mov	SCB_TARGET_STATUS, SCSIDATL
+	jmp	ITloop
 
 /*
  * Message out phase.  If there is not an active message, but the target
@@ -542,15 +542,22 @@ p_mesgout_start:
  * a MESSAGE REJECT.
  */
 p_mesgout_loop:
-	test	SSTAT0,SPIORDY jz p_mesgout_loop
-	test	SSTAT1,PHASEMIS	jnz p_mesgout_done
+	/*
+	 * If there is a parity error, wait for the kernel to
+	 * see the interrupt and "update" our message response
+	 * before continuing.
+	 */
+	test	SSTAT1, REQINIT	jz p_mesgout_loop
+	test	SSTAT1, SCSIPERR jnz p_mesgout_loop
+	and	LASTPHASE, PHASE_MASK, SCSISIGI
+	cmp	LASTPHASE, P_MESGOUT jne p_mesgout_done
 /*
  * 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.
  */
 p_mesgout_testretry:
 	test	DINDEX,0xff	jnz p_mesgout_dropatn
-	or	SCSISIGO,ATNO		/* turn on ATN for the retry */
+	or	SCSISIGO,ATNO,LASTPHASE	/* turn on ATN for the retry */
 	jmp	p_mesgout_start
 p_mesgout_dropatn:
 	cmp	DINDEX,1	jne p_mesgout_outb	/* last byte? */
@@ -649,16 +656,8 @@ status_ok:
 	mov	SCBPTR, SAVED_SCBPTR
 
 complete:
-	test	FLAGS, PAGESCBS jz complete_post
-	mov	A, QFULLCNT
-complete_poll:
-	cmp	QOUTQCNT, A	je complete_poll
-	mvi	SEQCTL,0x50			/* PAUSEDIS|FASTMODE */
-	inc	QOUTQCNT
-complete_post:
 	/* Post the SCB and issue an interrupt */
 	mov	QOUTFIFO,SCB_TAG
-	mvi	SEQCTL,0x10			/* FASTMODE */
 	mvi	INTSTAT,CMDCMPLT
 
 dma_next_scb:
@@ -701,7 +700,7 @@ mesgin_extended_intr:
 	cmp	RETURN_1,SEND_REJ je rej_mesgin
 	cmp	RETURN_1,SEND_MSG jne mesgin_done
 /* The kernel has setup a message to be sent */
-	or	SCSISIGO,ATNO			/* turn on ATNO */
+	or	SCSISIGO,ATNO,LASTPHASE		/* turn on ATNO */
 	jmp	mesgin_done
 
 /*
@@ -776,7 +775,8 @@ mesgin_identify:
 	mvi	ARG_1,SCB_LIST_NULL	/* Default to no-tag */
 snoop_tag_loop:
 	test	SSTAT1,REQINIT		jz snoop_tag_loop
-	test	SSTAT1,PHASEMIS		jnz use_findSCB
+	and	LASTPHASE, PHASE_MASK, SCSISIGI
+	cmp	LASTPHASE, P_MESGIN, jne use_findSCB
 	mvi	A			call inb_first
 	cmp	A,MSG_SIMPLE_Q_TAG	jne use_findSCB
 get_tag:
@@ -853,7 +853,7 @@ mk_mesg:
 	mvi	INTSTAT,MSG_BUFFER_BUSY
 
 mk_mesg1:
-	or	SCSISIGO,ATNO		/* turn on ATNO */
+	or	SCSISIGO,ATNO,LASTPHASE	/* turn on ATNO */
 	mvi	MSG_LEN,1		/* length = 1 */
 	mov	MSG0,SINDEX		/* 1-byte message */
 	mvi	SEQCTL,0x10	ret	/* !PAUSEDIS|FASTMODE */
@@ -875,15 +875,21 @@ mk_mesg1:
  */
 
 inb_next:
-	call	inb_last	/* ACK */
+	mov	NONE,SCSIDATL			/*dummy read from latch to ACK*/
 inb_next_wait:
-	test	SSTAT0, SPIORDY	jz inb_next_wait
-	test	SSTAT1,PHASEMIS	jnz mesgin_phasemis
+	/*
+	 * If there is a parity error, wait for the kernel to
+	 * see the interrupt and prepare our message response
+	 * before continuing.
+	 */
+	test	SSTAT1, REQINIT	jz inb_next_wait
+	test	SSTAT1, SCSIPERR jnz inb_next_wait
+	and	LASTPHASE, PHASE_MASK, SCSISIGI
+	cmp	LASTPHASE, P_MESGIN jne mesgin_phasemis
 inb_first:
 	mov	DINDEX,SINDEX
 	mov	DINDIR,SCSIBUSL	ret		/*read byte directly from bus*/
 inb_last:
-	mvi	CLRSINT0, CLRSPIORDY
 	mov	NONE,SCSIDATL ret		/*dummy read from latch to ACK*/
 
 mesgin_phasemis:
diff --git a/sys/dev/aic7xxx/aic7xxx_reg.h b/sys/dev/aic7xxx/aic7xxx_reg.h
index c4afb3b..a185792 100644
--- a/sys/dev/aic7xxx/aic7xxx_reg.h
+++ b/sys/dev/aic7xxx/aic7xxx_reg.h
@@ -320,6 +320,7 @@
 
 #define SINDEX			0x065
 #define DINDEX			0x066
+#define ALLONES			0x069
 #define ALLZEROS		0x06a
 #define NONE			0x06a
 #define SINDIR			0x06c
@@ -412,7 +413,6 @@
 #define			REJECT_MSG	0x61	/* Reject message received */
 #define			BAD_STATUS	0x71	/* Bad status from target */
 #define			RESIDUAL	0x81	/* Residual byte count != 0 */
-#define			ABORT_TAG	0x91	/* Sent an ABORT_TAG message */
 #define			AWAITING_MSG	0xa1	/*
 						 * Kernel requested to specify
                                                  * a message to this target
@@ -527,6 +527,7 @@
 #define		MK_MESSAGE      0x80
 #define		DISCENB         0x40
 #define		TAG_ENB		0x20
+#define		TRACE_SCB	0x10
 #define		ABORT_SCB	0x08
 #define		DISCONNECTED	0x04
 #define		SCB_TAG_TYPE	0x03