Fixes to the aic7xxx sequencer code and device driver from Justin Gibbs:

1) If a target initiated a sync negotiation with us and happened to chose a
value above 15, the old code inadvertantly truncated it with an "& 0x0f".
If the periferal picked something really bad like 0x32, you'd end up with
an offset of 2 which would hang the drive since it didn't expect to ever
get something so low.  We now do a MIN(maxoffset, given_offset).

2) In the case of Wide cards, we were turning on sync transfers after a
sucessfull wide negotiation.  Now we leave the offset alone in the per
target scratch space (which implies asyncronous transfers since we initialize
it that way) until a syncronous negotation occurs.

3) We were advertizing a max offset of 15 instead of 8 for wide devices.

4) If the upper level SCSI code sent down a "SCSI_RESET", it would hang the
system because we would end up sending a null command to the sequencer.  Now
we handle SCSI_RESET correctly by having the sequencer interrupt us when it
is about to fill the message buffer so that we can fill it in ourselves.
The sequencer will also "simulate" a command complete for these "message only"
SCBs so that the kernel driver can finish up properly.  The cdplay utility
will send a "SCSI_REST" to the cdplayer if you use the reset command.

5) The code that handles SCSIINTs was broken in that if more than one type
of error was true at once, we'd do outbs without the card being paused.
The else clause after the busfree case was also an accident waiting to
happen.  I've now turned this into an if, else if, else type of thing, since
in most cases when we handle one type of error, it should be okay to ignore
the rest (ie if we have a SELTO, who cares if there was a parity error on
the transaction?), but the section should really be rewritten after 2.0.5.
This fix was the least obtrusive way to patch the problem.

6) Only tag either SDTR or WDTR negotiation on an SCB.  The real problem is
that I don't account for the case when an SCB that is tagged to do a particular
type of negotiation completes or SELTOs (selection timeout) without the
negotiation taking place, so the accounting of sdtrpending and wdtrpending
gets screwed up.  In the wide case, if we tag it to do both wdtr and sdtr,
it only performs wdtr (since wdtr must occur first and we spread out the
negotiation over two commands) so we always have sdtrpending set for that
target and we never do a real SDTR.  I fill properly fix the accounting
after 2.0.5 goes out the door, but this works (as confirmed by Dan) on
wide targets.

Other stuff that is also included:

1) Don't do a bzero when recycling SCBs.  The only thing that must explicitly
be set to zero is the scb control byte which is done in ahc_get_scb.  We also
need to set the SG_list_pointer and SG_list_count to 0 for commands that do
not transfer data.

2) Mask the interrupt type printout for the aic7870 case.  The bit we were
using to determine interrupt type is only valid for the aic7770.


Submitted by:	Justin Gibbs

1 files changed, 41 insertions, 11 deletions

diff --git a/sys/dev/aic7xxx/aic7xxx.seq b/sys/dev/aic7xxx/aic7xxx.seq
index c5a1e9b..e8cc5bb 100644
--- a/sys/dev/aic7xxx/aic7xxx.seq
+++ b/sys/dev/aic7xxx/aic7xxx.seq
@@ -41,7 +41,7 @@
 #
 ##-M#########################################################################
 
-VERSION AIC7XXX_SEQ_VER "$Id: aic7xxx.seq,v 1.14 1995/04/15 21:45:56 gibbs Exp $"
+VERSION AIC7XXX_SEQ_VER "$Id: aic7xxx.seq,v 1.15 1995/04/27 17:44:27 gibbs Exp $"
 
 SCBMASK		= 0x1f
 
@@ -155,6 +155,12 @@ MSG_REJECT	= 0x61				# Reject message recieved
 BAD_STATUS	= 0x71				# Bad status from target
 RESIDUAL	= 0x81				# Residual byte count != 0
 ABORT_TAG	= 0x91				# Sent an ABORT_TAG message
+AWAITING_MSG	= 0xa1				# Kernel requested to specify
+						# a message to this target
+						# (command was null), so tell
+						# it that it can fill the
+						# message buffer.
+
 
 #  The host adapter card (at least the BIOS) uses 20-2f for SCSI
 #  device information, 32-33 and 5a-5f as well. As it turns out, the
@@ -179,8 +185,8 @@ ABORT_TAG	= 0x91				# Sent an ABORT_TAG message
 #  bank, so force a kernel panic if the target attempts a data in/out or
 #  command phase instead of corrupting something.  FLAGS also contains
 #  configuration bits so that we can optimize for TWIN and WIDE controllers
-#  as well as the MAX_SYNC bit which we set when we want to negotiate for
-#  10MHz irregardless of what the per target scratch space says.
+#  as well as the MAX_OFFSET bit which we set when we want to negotiate for
+#  maximum sync offset irregardless of what the per target scratch space says.
 #
 #  Note that SG_NEXT occupies four bytes.
 #
@@ -222,11 +228,14 @@ SCBCOUNT	= 0x52				# the actual number of SCBs
 FLAGS		= 0x53				# Device configuration flags
 TWIN_BUS	= 0x01
 WIDE_BUS	= 0x02
-MAX_SYNC	= 0x08
+MAX_OFFSET	= 0x08
 ACTIVE_MSG	= 0x20
 IDENTIFY_SEEN	= 0x40
 RESELECTED	= 0x80
 
+MAX_OFFSET_8BIT	= 0x0f
+MAX_OFFSET_WIDE	= 0x08
+
 ACTIVE_A	= 0x54
 ACTIVE_B	= 0x55
 SAVED_TCL	= 0x56				# Temporary storage for the 
@@ -369,6 +378,17 @@ start_selection:
 #  Messages are stored in scratch RAM starting with a flag byte (high bit
 #  set means active message), one length byte, and then the message itself.
 #
+
+	test	SCBARRAY+11,0xff jnz identify	# 0 Length Command?
+
+#  The kernel has sent us an SCB with no command attached.  This implies
+#  that the kernel wants to send a message of some sort to this target,
+#  so we interrupt the driver, allow it to fill the message buffer, and
+#  then go back into the arbitration loop
+	mvi     INTSTAT,AWAITING_MSG
+	jmp     poll_for_work
+
+identify:
 	mov	SCBARRAY+1	call disconnect	# disconnect ok?
 
 	and	SINDEX,0x7,SCBARRAY+1		# lun
@@ -682,6 +702,7 @@ clear_a:
 complete:
 	mov	QOUTFIFO,SCBPTR
 	mvi	INTSTAT,CMDCMPLT
+	test    SCBARRAY+11,0xff jz start	# Immediate message complete
 	jmp	p_mesgin_done
 
 # If we have a residual count, interrupt and tell the host.  Other
@@ -851,6 +872,10 @@ p_mesgin_done:
 p_busfree:
 	mvi	CLRSINT1,0x40			# CLRATNO
 	clr	SIGSTATE
+
+#  if this is an immediate command, perform a psuedo command complete to
+#  notify the driver.
+	test	SCBARRAY+11,0xff	jz status_ok
 	jmp	start
 
 #  Instead of a generic bcopy routine that requires an argument, we unroll
@@ -1202,7 +1227,7 @@ ndx_dtr_2:
 mk_dtr:
 	test	SCBARRAY+0,0xc0 jz return	# NEEDWDTR|NEEDSDTR
 	test	SCBARRAY+0,NEEDWDTR jnz  mk_wdtr_16bit
-	or	FLAGS, MAX_SYNC		 # Force an offset of 15
+	or	FLAGS, MAX_OFFSET	# Force an offset of 15 or 8 if WIDE
 
 mk_sdtr:
 	mvi	DINDIR,1			# extended message
@@ -1210,16 +1235,21 @@ mk_sdtr:
 	mvi	DINDIR,1			# SDTR code
 	call	sdtr_to_rate
 	mov	DINDIR,RETURN_1			# REQ/ACK transfer period
-	test	FLAGS, MAX_SYNC	jnz mk_sdtr_max_sync
-	and	DINDIR,0xf,SINDIR		# Sync Offset
+	test	FLAGS, MAX_OFFSET jnz mk_sdtr_max_offset
+	and	DINDIR,0x0f,SINDIR		# Sync Offset
 
 mk_sdtr_done:
 	add	MSG_LEN,-MSG_START+0,DINDEX ret	# update message length
 
-mk_sdtr_max_sync:
-# We're initiating sync negotiation, so request the max offset we can (15)
-	mvi	DINDIR, 0x0f
-	xor	FLAGS, MAX_SYNC
+mk_sdtr_max_offset:
+# We're initiating sync negotiation, so request the max offset we can (15 or 8)
+	xor	FLAGS, MAX_OFFSET
+	test	SCSIRATE, 0x80	jnz wmax_offset	# Talking to a WIDE device?
+	mvi	DINDIR, MAX_OFFSET_8BIT
+	jmp	mk_sdtr_done
+
+wmax_offset:
+	mvi	DINDIR, MAX_OFFSET_WIDE
 	jmp	mk_sdtr_done
 
 mk_wdtr_16bit: