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freebsd/sys/dev/aic7xxx/aic7xxx.seq

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# @(#)aic7xxx.seq 1.32 94/11/29 jda
#
# Adaptec 274x/284x/294x device driver for Linux and FreeBSD.
# Copyright (c) 1994 The University of Calgary Department of Computer Science.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#
# FreeBSD, Twin, Wide, 2 command per target support, tagged queuing and other
# optimizations provided by Justin T. Gibbs (gibbs@FreeBSD.org)
#
# $Id: aic7xxx.seq,v 1.7 1995/02/03 17:18:44 gibbs Exp $
VERSION AIC7XXX_SEQ_VERSION 1.8
SCBMASK = 0x1f
SCSISEQ = 0x00
SXFRCTL0 = 0x01
SXFRCTL1 = 0x02
SCSISIGI = 0x03
SCSISIGO = 0x03
SCSIRATE = 0x04
SCSIID = 0x05
SCSIDATL = 0x06
STCNT = 0x08
STCNT+0 = 0x08
STCNT+1 = 0x09
STCNT+2 = 0x0a
SSTAT0 = 0x0b
CLRSINT1 = 0x0c
SSTAT1 = 0x0c
SIMODE1 = 0x11
SCSIBUSL = 0x12
SHADDR = 0x14
SELID = 0x19
SBLKCTL = 0x1f
SEQCTL = 0x60
A = 0x64 # == ACCUM
SINDEX = 0x65
DINDEX = 0x66
ALLZEROS = 0x6a
NONE = 0x6a
SINDIR = 0x6c
DINDIR = 0x6d
FUNCTION1 = 0x6e
HADDR = 0x88
HCNT = 0x8c
HCNT+0 = 0x8c
HCNT+1 = 0x8d
HCNT+2 = 0x8e
SCBPTR = 0x90
INTSTAT = 0x91
DFCNTRL = 0x93
DFSTATUS = 0x94
DFDAT = 0x99
QINFIFO = 0x9b
QINCNT = 0x9c
QOUTFIFO = 0x9d
SCSICONF_A = 0x5a
SCSICONF_B = 0x5b
# The two reserved bytes at SCBARRAY+1[23] are expected to be set to
# zero, and the reserved bit in SCBARRAY+0 is used as an internal flag
# to indicate whether or not to reload scatter-gather parameters after
# a disconnect. We also use bits 6 & 7 to indicate whether or not to
# initiate SDTR or WDTR repectively when starting this command.
#
SCBARRAY+0 = 0xa0
DISCONNECTED = 0x04
NEEDDMA = 0x08
SG_LOAD = 0x10
TAG_ENB = 0x20
NEEDSDTR = 0x40
NEEDWDTR = 0x80
SCBARRAY+1 = 0xa1
SCBARRAY+2 = 0xa2
SCBARRAY+3 = 0xa3
SCBARRAY+4 = 0xa4
SCBARRAY+5 = 0xa5
SCBARRAY+6 = 0xa6
SCBARRAY+7 = 0xa7
SCBARRAY+8 = 0xa8
SCBARRAY+9 = 0xa9
SCBARRAY+10 = 0xaa
SCBARRAY+11 = 0xab
SCBARRAY+12 = 0xac
SCBARRAY+13 = 0xad
SCBARRAY+14 = 0xae
SCBARRAY+15 = 0xaf
SCBARRAY+16 = 0xb0
SCBARRAY+17 = 0xb1
SCBARRAY+18 = 0xb2
SCBARRAY+19 = 0xb3
SCBARRAY+20 = 0xb4
SCBARRAY+21 = 0xb5
SCBARRAY+22 = 0xb6
SCBARRAY+23 = 0xb7
SCBARRAY+24 = 0xb8
SCBARRAY+25 = 0xb9
SCBARRAY+26 = 0xba
BAD_PHASE = 0x01 # unknown scsi bus phase
SEND_REJECT = 0x11 # sending a message reject
NO_IDENT = 0x21 # no IDENTIFY after reconnect
NO_MATCH = 0x31 # no cmd match for reconnect
MSG_SDTR = 0x41 # SDTR message recieved
MSG_WDTR = 0x51 # WDTR message recieved
MSG_REJECT = 0x61 # Reject message recieved
BAD_STATUS = 0x71 # Bad status from target
# 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
# BIOS trashes 20-2f, writing the synchronous negotiation results
# on top of the BIOS values, so we re-use those for our per-target
# scratchspace (actually a value that can be copied directly into
# SCSIRATE). The kernel driver will enable synchronous negotiation
# for all targets that have a value other than 0 in the lower four
# bits of the target scratch space. This should work irregardless of
# whether the bios has been installed. NEEDWDTR and NEEDSDTR are the top
# two bits of the SCB control byte. The kernel driver will set these
# when a WDTR or SDTR message should be sent to the target the SCB's
# command references.
#
# The high bit of DROPATN is set if ATN should be dropped before the ACK
# when outb is called. REJBYTE contains the first byte of a MESSAGE IN
# message, so the driver can report an intelligible error if a message is
# rejected.
#
# FLAGS's high bit is true if we are currently handling a reselect;
# its next-highest bit is true ONLY IF we've seen an IDENTIFY message
# from the reselecting target. If we haven't had IDENTIFY, then we have
# no idea what the lun is, and we can't select the right SCB register
# bank, so force a kernel panic if the target attempts a data in/out or
# command phase instead of corrupting something.
#
# Note that SG_NEXT occupies four bytes.
#
SYNCNEG = 0x20
DROPATN = 0x30
REJBYTE = 0x31
DISC_DSB_A = 0x32
DISC_DSB_B = 0x33
MSG_LEN = 0x34
MSG_START+0 = 0x35
MSG_START+1 = 0x36
MSG_START+2 = 0x37
MSG_START+3 = 0x38
MSG_START+4 = 0x39
MSG_START+5 = 0x3a
-MSG_START+0 = 0xcb # 2's complement of MSG_START+0
ARG_1 = 0x4a # sdtr conversion args & return
BUS_16_BIT = 0x01
RETURN_1 = 0x4a
SIGSTATE = 0x4b # value written to SCSISIGO
# Linux users should use 0xc (12) for SG_SIZEOF
SG_SIZEOF = 0x8 # sizeof(struct ahc_dma)
#SG_SIZEOF = 0xc # sizeof(struct scatterlist)
SCB_SIZEOF = 0x13 # sizeof SCB to DMA (19 bytes)
SG_NOLOAD = 0x4c # load SG pointer/length?
SG_COUNT = 0x4d # working value of SG count
SG_NEXT = 0x4e # working value of SG pointer
SG_NEXT+0 = 0x4e
SG_NEXT+1 = 0x4f
SG_NEXT+2 = 0x50
SG_NEXT+3 = 0x51
SCBCOUNT = 0x52 # the actual number of SCBs
FLAGS = 0x53 # Device configuration flags
TWIN_BUS = 0x01
WIDE_BUS = 0x02
SELECTED_SCB = 0x08
SENSE = 0x10
ACTIVE_MSG = 0x20
IDENTIFY_SEEN = 0x40
RESELECTED = 0x80
ACTIVE_A = 0x54
ACTIVE_B = 0x55
SAVED_TCL = 0x56
# Poll QINCNT for work - the lower bits contain
# the number of entries in the Queue In FIFO.
#
start:
test FLAGS,SENSE jnz start_sense
start_nosense:
test FLAGS,TWIN_BUS jz start2 # Are we a twin channel device?
# For fairness, we check the other bus first, since we just finished a
# transaction on the current channel.
xor SBLKCTL,0x08 # Toggle to the other bus
test SCSISIGI,0x4 jnz reselect # BSYI
xor SBLKCTL,0x08 # Toggle to the original bus
start2:
test SCSISIGI,0x4 jnz reselect # BSYI
test QINCNT,SCBMASK jz start_nosense
# We have at least one queued SCB now. Set the SCB pointer
# from the FIFO so we see the right bank of SCB registers,
# then set SCSI options and set the initiator and target
# SCSI IDs.
#
mov SCBPTR,QINFIFO
# If the control byte of this SCB has the NEEDDMA flag set, we have
# yet to DMA it from host memory
test SCBARRAY+0,NEEDDMA jz test_busy
clr HCNT+2
clr HCNT+1
mvi HCNT+0,SCB_SIZEOF
mvi DINDEX,HADDR
mvi SCBARRAY+26 call bcopy_4
mvi DFCNTRL,0xd # HDMAEN|DIRECTION|FIFORESET
# Wait for DMA from host memory to data FIFO to complete, then disable
# DMA and wait for it to acknowledge that it's off.
#
scb_load1:
test DFSTATUS,0x8 jz scb_load1 # HDONE
clr DFCNTRL # disable DMA
scb_load2:
test DFCNTRL,0x8 jnz scb_load2 # HDMAENACK
# Copy the SCB from the FIFO to the SCBARRAY
mov SCBARRAY+0, DFDAT
mov SCBARRAY+1, DFDAT
mov SCBARRAY+2, DFDAT
mov SCBARRAY+3, DFDAT
mov SCBARRAY+4, DFDAT
mov SCBARRAY+5, DFDAT
mov SCBARRAY+6, DFDAT
mov SCBARRAY+7, DFDAT
mov SCBARRAY+8, DFDAT
mov SCBARRAY+9, DFDAT
mov SCBARRAY+10, DFDAT
mov SCBARRAY+11, DFDAT
mov SCBARRAY+12, DFDAT
mov SCBARRAY+13, DFDAT
mov SCBARRAY+14, DFDAT
mov SCBARRAY+15, DFDAT
mov SCBARRAY+16, DFDAT
mov SCBARRAY+17, DFDAT
mov SCBARRAY+18, DFDAT
# See if there is not already an active SCB for this target. This code
# locks out on a per target basis instead of target/lun. Although this
# is not ideal for devices that have multiple luns active at the same
# time, it is faster than looping through all SCB's looking for active
# commands. It may be benificial to make findscb a more general procedure
# to see if the added cost of the search is negligible. This code also
# assumes that the kernel driver will clear the active flags on board
# initialization, board reset, and a target's SELTO.
test_busy:
test SCBARRAY+0,0x20 jnz start_scb
and FUNCTION1,0x70,SCBARRAY+1
mov A,FUNCTION1
test SCBARRAY+1,0x88 jz test_a # Id < 8 && A channel
test ACTIVE_B,A jnz requeue
or ACTIVE_B,A # Mark the current target as busy
jmp start_scb
start_sense:
# Clear the SENSE flag first, then do a normal start_scb
and FLAGS,0xef
jmp start_scb
# Place the currently active back on the queue for later processing
requeue:
mov QINFIFO, SCBPTR
jmp start_nosense
test_a:
test ACTIVE_A,A jnz requeue
or ACTIVE_A,A # Mark the current target as busy
start_scb:
or SCBARRAY+0,NEEDDMA
and SINDEX,0x08,SCBARRAY+1
and A,WIDE_BUS,FLAGS # Wide bus?
or SINDEX,A
mov SBLKCTL,SINDEX # select channel, bus width
mov SCBARRAY+1 call initialize
clr SG_NOLOAD
and FLAGS,0x3f # !RESELECTING
# As soon as we get a successful selection, the target should go
# into the message out phase since we have ATN asserted. Prepare
# the message to send, locking out the device driver. If the device
# driver hasn't beaten us with an ABORT or RESET message, then tack
# on an SDTR negotiation if required.
#
# 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.
#
mov SCBARRAY+1 call disconnect # disconnect ok?
and SINDEX,0x7,SCBARRAY+1 # lun
or SINDEX,A # return value from disconnect
or SINDEX,0x80 call mk_mesg # IDENTIFY message
mov A,SINDEX
test SCBARRAY+0,0xe0 jz !message # WDTR, SDTR or TAG??
cmp MSG_START+0,A jne !message # did driver beat us?
# Tag Message if Tag enabled in SCB control block. Use SCBPTR as the tag
# value
mk_tag:
mvi DINDEX, MSG_START+1
test SCBARRAY+0,TAG_ENB jz mk_tag_done
and A,0x23,SCBARRAY+0
mov DINDIR,A
mov DINDIR,SCBPTR
add MSG_LEN,-MSG_START+0,DINDEX # update message length
jmp !message # Can't do DTR when taged
mk_tag_done:
mov DINDEX call mk_dtr # build DTR message if needed
!message:
# Enable selection phase as an initiator, and do automatic ATN
# after the selection.
#
mvi SCSISEQ,0x48 # ENSELO|ENAUTOATNO
# Wait for successful arbitration. The AIC-7770 documentation says
# that SELINGO indicates successful arbitration, and that it should
# be used to look for SELDO. However, if the sequencer is paused at
# just the right time - a parallel fsck(8) on two drives did it for
# me - then SELINGO can flip back to false before we've seen it. This
# makes the sequencer sit in the arbitration loop forever. This is
# Not Good.
#
# Therefore, I've added a check in the arbitration loop for SELDO
# too. This could arguably be made a critical section by disabling
# pauses, but I don't want to make a potentially infinite loop a CS.
# I suppose you could fold it into the select loop, too, but since
# I've been hunting this bug for four days it's kinda like a trophy.
#
arbitrate:
test SSTAT0,0x40 jnz *select # SELDO
test SSTAT0,0x10 jz arbitrate # SELINGO
# Wait for a successful selection. If the hardware selection
# timer goes off, then the driver gets the interrupt, so we don't
# need to worry about it.
#
select:
test SSTAT0,0x40 jz select # SELDO
jmp *select
# Reselection is being initiated by a target - we've seen the BSY
# line driven active, and we didn't do it! Enable the reselection
# hardware, and wait for it to finish. Make a note that we've been
# reselected, but haven't seen an IDENTIFY message from the target
# yet.
#
reselect:
mvi SCSISEQ,0x10 # ENRSELI
reselect1:
test SSTAT0,0x20 jz reselect1 # SELDI
mov SELID call initialize
and FLAGS,0x3f # reselected, no IDENTIFY
or FLAGS,RESELECTED
# After the [re]selection, make sure that the [re]selection enable
# bit is off. This chip is flaky enough without extra things
# turned on. Also clear the BUSFREE bit in SSTAT1 since we'll be
# using it shortly.
#
*select:
clr SCSISEQ
mvi CLRSINT1,0x8 # CLRBUSFREE
# Main loop for information transfer phases. If BSY is false, then
# we have a bus free condition, expected or not. Otherwise, wait
# for the target to assert REQ before checking MSG, C/D and I/O
# for the bus phase.
#
# We can't simply look at the values of SCSISIGI here (if we want
# to do synchronous data transfer), because the target won't assert
# REQ if it's already sent us some data that we haven't acknowledged
# yet.
#
ITloop:
test SSTAT1,0x8 jnz p_busfree # BUSFREE
test SSTAT1,0x1 jz ITloop # REQINIT
and A,0xe0,SCSISIGI # CDI|IOI|MSGI
cmp ALLZEROS,A je p_dataout
cmp A,0x40 je p_datain
cmp A,0x80 je p_command
cmp A,0xc0 je p_status
cmp A,0xa0 je p_mesgout
cmp A,0xe0 je p_mesgin
mvi INTSTAT,BAD_PHASE # unknown - signal driver
p_dataout:
mvi 0 call scsisig # !CDO|!IOO|!MSGO
call assert
call sg_load
mvi DINDEX,HADDR
mvi SCBARRAY+19 call bcopy_4
# mvi DINDEX,HCNT # implicit since HCNT is next to HADDR
mvi SCBARRAY+23 call bcopy_3
mvi DINDEX,STCNT
mvi SCBARRAY+23 call bcopy_3
mvi 0x3d call dma # SCSIEN|SDMAEN|HDMAEN|
# DIRECTION|FIFORESET
# After a DMA finishes, save the final transfer pointer and count
# back into the SCB, in case a device disconnects in the middle of
# a transfer. Use SHADDR and STCNT instead of HADDR and HCNT, since
# it's a reflection of how many bytes were transferred on the SCSI
# (as opposed to the host) bus.
#
mvi DINDEX,SCBARRAY+23
mvi STCNT call bcopy_3
mvi DINDEX,SCBARRAY+19
mvi SHADDR call bcopy_4
call sg_advance
mov SCBARRAY+18,SG_COUNT # residual S/G count
jmp ITloop
p_datain:
mvi 0x40 call scsisig # !CDO|IOO|!MSGO
call assert
call sg_load
mvi DINDEX,HADDR
mvi SCBARRAY+19 call bcopy_4
# mvi DINDEX,HCNT # implicit since HCNT is next to HADDR
mvi SCBARRAY+23 call bcopy_3
mvi DINDEX,STCNT
mvi SCBARRAY+23 call bcopy_3
mvi 0x39 call dma # SCSIEN|SDMAEN|HDMAEN|
# !DIRECTION|FIFORESET
mvi DINDEX,SCBARRAY+23
mvi STCNT call bcopy_3
mvi DINDEX,SCBARRAY+19
mvi SHADDR call bcopy_4
call sg_advance
mov SCBARRAY+18,SG_COUNT # residual S/G count
jmp ITloop
# Command phase. Set up the DMA registers and let 'er rip - the
# two bytes after the SCB SCSI_cmd_length are zeroed by the driver,
# so we can copy those three bytes directly into HCNT.
#
p_command:
mvi 0x80 call scsisig # CDO|!IOO|!MSGO
call assert
mvi DINDEX,HADDR
mvi SCBARRAY+7 call bcopy_4
# mvi DINDEX,HCNT # implicit since HCNT is next to HADDR
mvi SCBARRAY+11 call bcopy_3
mvi DINDEX,STCNT
mvi SCBARRAY+11 call bcopy_3
mvi 0x3d call dma # SCSIEN|SDMAEN|HDMAEN|
# DIRECTION|FIFORESET
jmp ITloop
# Status phase. Wait for the data byte to appear, then read it
# and store it into the SCB.
#
p_status:
mvi 0xc0 call scsisig # CDO|IOO|!MSGO
mvi SCBARRAY+14 call inb
jmp ITloop
# Message out phase. If there is no active message, but the target
# took us into this phase anyway, build a no-op message and send it.
#
p_mesgout:
mvi 0xa0 call scsisig # CDO|!IOO|MSGO
mvi 0x8 call mk_mesg # build NOP message
# Set up automatic PIO transfer from MSG_START. Bit 3 in
# SXFRCTL0 (SPIOEN) is already on.
#
mvi SINDEX,MSG_START+0
mov DINDEX,MSG_LEN
clr A
# When target asks for a byte, drop ATN if it's the last one in
# the message. Otherwise, keep going until the message is exhausted.
# (We can't use outb for this since it wants the input in SINDEX.)
#
# Keep an eye out for a phase change, in case the target issues
# a MESSAGE REJECT.
#
p_mesgout2:
test SSTAT0,0x2 jz p_mesgout2 # SPIORDY
test SSTAT1,0x10 jnz p_mesgout6 # PHASEMIS
cmp DINDEX,1 jne p_mesgout3 # last byte?
mvi CLRSINT1,0x40 # CLRATNO - drop ATN
# Write a byte to the SCSI bus. The AIC-7770 refuses to automatically
# send ACKs in automatic PIO or DMA mode unless you make sure that the
# "expected" bus phase in SCSISIGO matches the actual bus phase. This
# behaviour is completely undocumented and caused me several days of
# grief.
#
# After plugging in different drives to test with and using a longer
# SCSI cable, I found that I/O in Automatic PIO mode ceased to function,
# especially when transferring >1 byte. It seems to be much more stable
# if STCNT is set to one before the transfer, and SDONE (in SSTAT0) is
# polled for transfer completion - for both output _and_ input. The
# only theory I have is that SPIORDY doesn't drop right away when SCSIDATL
# is accessed (like the documentation says it does), and that on a longer
# cable run, the sequencer code was fast enough to loop back and see
# an SPIORDY that hadn't dropped yet.
#
p_mesgout3:
call one_stcnt
mov SCSIDATL,SINDIR
p_mesgout4:
test SSTAT0,0x4 jz p_mesgout4 # SDONE
dec DINDEX
inc A
cmp MSG_LEN,A jne p_mesgout2
# 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_mesgout5:
test SSTAT1,0x8 jnz p_mesgout6 # BUSFREE
test SSTAT1,0x1 jz p_mesgout5 # REQINIT
and A,0xe0,SCSISIGI # CDI|IOI|MSGI
cmp A,0xa0 jne p_mesgout6
mvi 0x10 call scsisig # ATNO - re-assert ATN
jmp ITloop
p_mesgout6:
mvi CLRSINT1,0x40 # CLRATNO - in case of PHASEMIS
and FLAGS,0xdf # no active msg
jmp ITloop
# Message in phase. Bytes are read using Automatic PIO mode, but not
# using inb. This alleviates a race condition, namely that if ATN had
# to be asserted under Automatic PIO mode, it had to beat the SCSI
# circuitry sending an ACK to the target. This showed up under heavy
# loads and really confused things, since ABORT commands wouldn't be
# seen by the drive after an IDENTIFY message in until it had changed
# to a data I/O phase.
#
p_mesgin:
mvi 0xe0 call scsisig # CDO|IOO|MSGO
mvi A call inb_first # read the 1st message byte
mvi REJBYTE,A # save it for the driver
cmp ALLZEROS,A jne p_mesgin1
# We got a "command complete" message, so put the SCB pointer
# into the Queue Out, and trigger a completion interrupt.
# Check status for non zero return and interrupt driver if needed
# This allows the driver to interpret errors only when they occur
# instead of always uploading the scb. If the status is SCSI_CHECK,
# the driver will download a new scb requesting sense, to replace
# the old one and the sequencer code will imediately jump to start
# working on it. If the kernel driver does not wish to request sense,
# the sequencer program counter is incremented by 1, preventing another run
# on the current SCB and the command is allowed to complete. We don't
# bother to post to the QOUTFIFO in the error case 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.
test SCBARRAY+14,0xff jz status_ok # 0 Status?
mvi INTSTAT,BAD_STATUS # let driver know
test FLAGS,SENSE jz status_ok
jmp p_mesgin_done
status_ok:
# First, mark this target as free.
test SCBARRAY+0,0x20 jnz complete # Tagged command
and FUNCTION1,0x70,SCBARRAY+1
mov A,FUNCTION1
test SCBARRAY+1,0x88 jz clear_a
xor ACTIVE_B,A
jmp complete
clear_a:
xor ACTIVE_A,A
complete:
mov QOUTFIFO,SCBPTR
mvi INTSTAT,0x02 # CMDCMPLT
jmp p_mesgin_done
# Is it an extended message? We only support the synchronous and wide data
# transfer request messages, which will probably be in response to
# WDTR or SDTR message outs from us. If it's not SDTR or WDTR, reject it -
# apparently this can be done after any message in byte, according
# to the SCSI-2 spec.
#
p_mesgin1:
cmp A,1 jne p_mesgin2 # extended message code?
mvi ARG_1 call inb_next # extended message length
mvi A call inb_next # extended message code
cmp A,1 je p_mesginSDTR # Syncronous negotiation message
cmp A,3 je p_mesginWDTR # Wide negotiation message
jmp p_mesginN
p_mesginWDTR:
cmp ARG_1,2 jne p_mesginN # extended mesg length = 2
mvi A call inb_next # Width of bus
mvi INTSTAT,MSG_WDTR # let driver know
test RETURN_1,0x80 jz p_mesgin_done# Do we need to send WDTR?
# We didn't initiate the wide negotiation, so we must respond to the request
and RETURN_1,0x7f # Clear the SEND_WDTR Flag
or FLAGS,ACTIVE_MSG
mvi DINDEX,MSG_START+0
mvi MSG_START+0 call mk_wdtr # build WDTR message
or SINDEX,0x10,SIGSTATE # turn on ATNO
call scsisig
jmp p_mesgin_done
p_mesginSDTR:
cmp ARG_1,3 jne p_mesginN # extended mesg length = 3
mvi ARG_1 call inb_next # xfer period
mvi A call inb_next # REQ/ACK offset
mvi INTSTAT,MSG_SDTR # call driver to convert
test RETURN_1,0x80 jz p_mesgin_done# Do we need to mk_sdtr?
or FLAGS,ACTIVE_MSG
mvi DINDEX, MSG_START+0
mvi MSG_START+0 call mk_sdtr
or SINDEX,0x10,SIGSTATE # turn on ATNO
call scsisig
jmp p_mesgin_done
# Is it a disconnect message? Set a flag in the SCB to remind us
# and await the bus going free.
#
p_mesgin2:
cmp A,4 jne p_mesgin3 # disconnect code?
or SCBARRAY+0,0x4 # set "disconnected" bit
jmp p_mesgin_done
# Save data pointers message? Copy working values into the SCB,
# usually in preparation for a disconnect.
#
p_mesgin3:
cmp A,2 jne p_mesgin4 # save data pointers code?
call sg_ram2scb
jmp p_mesgin_done
# Restore pointers message? Data pointers are recopied from the
# SCB anyway at the start of any DMA operation, so the only thing
# to copy is the scatter-gather values.
#
p_mesgin4:
cmp A,3 jne p_mesgin5 # restore pointers code?
call sg_scb2ram
jmp p_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.
#
p_mesgin5:
test A,0x80 jz p_mesgin6 # identify message?
test A,0x78 jnz p_mesginN # !DiscPriv|!LUNTAR|!Reserved
and A,0x7 # lun in lower three bits
or SAVED_TCL,A,SELID
and SAVED_TCL,0xf7
and A,0x08,SBLKCTL # B Channel??
or SAVED_TCL,A
call inb_last # Ack
# Here we "snoop" the bus looking for a SIMPLE QUEUE TAG message.
# If we get one, we use the tag returned to switch to the proper
# SCB. Otherwise, we just use the findSCB method.
p_mesgin5_loop:
test SSTAT1,0x8 jnz use_findSCB # BUSFREE
test SSTAT1,0x1 jz p_mesgin5_loop # REQINIT
and A,0xe0,SCSISIGI # CDI|IOI|MSGI
cmp A,0xe0 jne use_findSCB # Still p_mesgin?
mvi A call inb_first
cmp A,0x20 je get_tag # Simple Tag message?
use_findSCB:
mov ALLZEROS call findSCB # Have to search
# If a active message is present after calling findSCB, then either it
# or the driver is trying to abort the command. Either way, something
# untoward has happened and we should just leave it alone.
#
setup_SCB:
test FLAGS,ACTIVE_MSG jnz p_mesgin_done
and SCBARRAY+0,0xfb # clear disconnect bit in SCB
or FLAGS,0xc0 # make note of IDENTIFY
call sg_scb2ram # implied restore pointers
# required on reselect
jmp ITloop
get_tag:
mvi A call inb_next
test A,0xf0 jnz abort_tag # Tag in range?
mov SCBPTR,A
mov A,SAVED_TCL
cmp SCBARRAY+1,A jne abort_tag
test SCBARRAY+0,TAG_ENB jz abort_tag
call inb_last
jmp setup_SCB
# Message reject? Let the kernel driver handle this. If we have an
# outstanding WDTR or SDTR negotiation, assume that it's a response from
# the target selecting 8bit or asynchronous transfer, otherwise just ignore
# it since we have no clue what it pertains to.
#
p_mesgin6:
cmp A,7 jne p_mesgin7 # message reject code?
mvi INTSTAT, MSG_REJECT
jmp p_mesgin_done
# [ ADD MORE MESSAGE HANDLING HERE ]
#
p_mesgin7:
# We have no idea what this message in is, and there's no way
# to pass it up to the kernel, so we issue a message reject and
# hope for the best. Since we're now using manual PIO mode to
# read in the message, there should no longer be a race condition
# present when we assert ATN. In any case, rejection should be a
# rare occurrence - signal the driver when it happens.
#
p_mesginN:
or SINDEX,0x10,SIGSTATE # turn on ATNO
call scsisig
mvi INTSTAT,SEND_REJECT # let driver know
mvi 0x7 call mk_mesg # MESSAGE REJECT message
p_mesgin_done:
call inb_last # ack & turn auto PIO back on
jmp ITloop
abort_tag:
or SINDEX,0x10,SIGSTATE # turn on ATNO
call scsisig
# mvi INTSTAT,ABORT_TAG # let driver know
mvi 0xd call mk_mesg # ABORT TAG message
jmp p_mesgin_done
# Bus free phase. It might be useful to interrupt the device
# driver if we aren't expecting this. For now, make sure that
# ATN isn't being asserted and look for a new command.
#
p_busfree:
mvi CLRSINT1,0x40 # CLRATNO
clr SIGSTATE
jmp start
# Instead of a generic bcopy routine that requires an argument, we unroll
# the two cases that are actually used, and call them explicitly. This
# not only reduces the overhead of doing a bcopy by 2/3rds, but ends up
# saving space in the program since you don't have to put the argument
# into the accumulator before the call. Both functions expect DINDEX to
# contain the destination address and SINDEX to contain the source
# address.
bcopy_3:
mov DINDIR,SINDIR
mov DINDIR,SINDIR
mov DINDIR,SINDIR ret
bcopy_4:
mov DINDIR,SINDIR
mov DINDIR,SINDIR
mov DINDIR,SINDIR
mov DINDIR,SINDIR ret
# Locking the driver out, build a one-byte message passed in SINDEX
# if there is no active message already. SINDEX is returned intact.
#
mk_mesg:
mvi SEQCTL,0x50 # PAUSEDIS|FASTMODE
test FLAGS,ACTIVE_MSG jnz mk_mesg1 # active message?
or FLAGS,ACTIVE_MSG # if not, there is now
mvi MSG_LEN,1 # length = 1
mov MSG_START+0,SINDEX # 1-byte message
mk_mesg1:
mvi SEQCTL,0x10 ret # !PAUSEDIS|FASTMODE
# Input byte in Automatic PIO mode. The address to store the byte
# in should be in SINDEX. DINDEX will be used by this routine.
#
inb:
test SSTAT0,0x2 jz inb # SPIORDY
mov DINDEX,SINDEX
call one_stcnt # xfer one byte
mov DINDIR,SCSIDATL
inb1:
test SSTAT0,0x4 jz inb1 # SDONE - wait to "finish"
ret
# Carefully read data in Automatic PIO mode. I first tried this using
# Manual PIO mode, but it gave me continual underrun errors, probably
# indicating that I did something wrong, but I feel more secure leaving
# Automatic PIO on all the time.
#
# According to Adaptec's documentation, an ACK is not sent on input from
# the target until SCSIDATL is read from. So we wait until SCSIDATL is
# latched (the usual way), then read the data byte directly off the bus
# using SCSIBUSL. When we have pulled the ATN line, or we just want to
# acknowledge the byte, then we do a dummy read from SCISDATL. The SCSI
# spec guarantees that the target will hold the data byte on the bus until
# we send our ACK.
#
# The assumption here is that these are called in a particular sequence,
# and that REQ is already set when inb_first is called. inb_{first,next}
# use the same calling convention as inb.
#
inb_first:
mov DINDEX,SINDEX
mov DINDIR,SCSIBUSL ret # read byte directly from bus
inb_next:
mov DINDEX,SINDEX # save SINDEX
call one_stcnt # xfer one byte
mov NONE,SCSIDATL # dummy read from latch to ACK
inb_next1:
test SSTAT0,0x4 jz inb_next1 # SDONE
inb_next2:
test SSTAT0,0x2 jz inb_next2 # SPIORDY - wait for next byte
mov DINDIR,SCSIBUSL ret # read byte directly from bus
inb_last:
call one_stcnt # ACK with dummy read
mov NONE,SCSIDATL
inb_last1:
test SSTAT0,0x4 jz inb_last1 # wait for completion
ret
# Output byte in Automatic PIO mode. The byte to output should be
# in SINDEX. If DROPATN's high bit is set, then ATN will be dropped
# before the byte is output.
#
outb:
test SSTAT0,0x2 jz outb # SPIORDY
call one_stcnt # xfer one byte
test DROPATN,0x80 jz outb1
mvi CLRSINT1,0x40 # CLRATNO
clr DROPATN
outb1:
mov SCSIDATL,SINDEX
outb2:
test SSTAT0,0x4 jz outb2 # SDONE
ret
# Write the value "1" into the STCNT registers, for Automatic PIO
# transfers.
#
one_stcnt:
clr STCNT+2
clr STCNT+1
mvi STCNT+0,1 ret
# DMA data transfer. HADDR and HCNT must be loaded first, and
# SINDEX should contain the value to load DFCNTRL with - 0x3d for
# host->scsi, or 0x39 for scsi->host. The SCSI channel is cleared
# during initialization.
#
dma:
mov DFCNTRL,SINDEX
dma1:
dma2:
test SSTAT0,0x1 jnz dma3 # DMADONE
test SSTAT1,0x10 jz dma1 # PHASEMIS, ie. underrun
# We will be "done" DMAing when the transfer count goes to zero, or
# the target changes the phase (in light of this, it makes sense that
# the DMA circuitry doesn't ACK when PHASEMIS is active). If we are
# doing a SCSI->Host transfer, the data FIFO should be flushed auto-
# magically on STCNT=0 or a phase change, so just wait for FIFO empty
# status.
#
dma3:
test SINDEX,0x4 jnz dma5 # DIRECTION
dma4:
test DFSTATUS,0x1 jz dma4 # !FIFOEMP
# Now shut the DMA enables off, and copy STCNT (ie. the underrun
# amount, if any) to the SCB registers; SG_COUNT will get copied to
# the SCB's residual S/G count field after sg_advance is called. Make
# sure that the DMA enables are actually off first lest we get an ILLSADDR.
#
dma5:
clr DFCNTRL # disable DMA
dma6:
test DFCNTRL,0x38 jnz dma6 # SCSIENACK|SDMAENACK|HDMAENACK
mvi DINDEX,SCBARRAY+15
mvi STCNT call bcopy_3
ret
# Common SCSI initialization for selection and reselection. Expects
# the target SCSI ID to be in the upper four bits of SINDEX, and A's
# contents are stomped on return.
#
initialize:
and SINDEX,0xf0 # Get target ID
and A,0x0f,SCSIID
or SINDEX,A
mov SCSIID,SINDEX
# Esundry initialization.
#
clr DROPATN
clr SIGSTATE
# Turn on Automatic PIO mode now, before we expect to see a REQ
# from the target. It shouldn't hurt anything to leave it on. 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.
#
mvi SXFRCTL0,0x8a # DFON|SPIOEN|CLRCHN
# Initialize scatter-gather pointers by setting up the working copy
# in scratch RAM.
#
call sg_scb2ram
# Initialize SCSIRATE with the appropriate value for this target.
#
call ndx_dtr
mov SCSIRATE,SINDIR ret
# Assert that if we've been reselected, then we've seen an IDENTIFY
# message.
#
assert:
test FLAGS,RESELECTED jz assert1 # reselected?
test FLAGS,IDENTIFY_SEEN jnz assert1 # seen IDENTIFY?
mvi INTSTAT,NO_IDENT # no - cause a kernel panic
assert1:
ret
# Find out if disconnection is ok from the information the BIOS has left
# us. The tcl from SCBARRAY+1 should be in SINDEX; A will
# contain either 0x40 (disconnection ok) or 0x00 (disconnection not ok)
# on exit.
#
# To allow for wide or twin busses, we check the upper bit of the target ID
# and the channel ID and look at the appropriate disconnect register.
#
disconnect:
and FUNCTION1,0x70,SINDEX # strip off extra just in case
mov A,FUNCTION1
test SINDEX, 0x88 jz disconnect_a
test DISC_DSB_B,A jz disconnect1 # bit nonzero if DISabled
clr A ret
disconnect_a:
test DISC_DSB_A,A jz disconnect1 # bit nonzero if DISabled
clr A ret
disconnect1:
mvi A,0x40 ret
# Locate the SCB matching the target ID/channel/lun in SAVED_TCL and switch
# the SCB to it. Have the kernel print a warning message if it can't be
# found, and generate an ABORT message to the target. SINDEX should be
# cleared on call.
#
findSCB:
mov A,SAVED_TCL
mov SCBPTR,SINDEX # switch to new SCB
cmp SCBARRAY+1,A jne findSCB1 # target ID/channel/lun match?
test SCBARRAY+0,0x4 jz findSCB1 # should be disconnected
ret
findSCB1:
inc SINDEX
mov A,SCBCOUNT
cmp SINDEX,A jne findSCB
mvi INTSTAT,NO_MATCH # not found - signal kernel
mvi 0x6 call mk_mesg # ABORT message
or SINDEX,0x10,SIGSTATE # assert ATNO
call scsisig
ret
# Make a working copy of the scatter-gather parameters in the SCB.
#
sg_scb2ram:
mov SG_COUNT,SCBARRAY+2
mvi DINDEX,SG_NEXT
mvi SCBARRAY+3 call bcopy_4
mvi SG_NOLOAD,0x80
test SCBARRAY+0,0x10 jnz sg_scb2ram1 # don't reload s/g?
clr SG_NOLOAD
sg_scb2ram1:
ret
# Copying RAM values back to SCB, for Save Data Pointers message.
#
sg_ram2scb:
mov SCBARRAY+2,SG_COUNT
mvi DINDEX,SCBARRAY+3
mvi SG_NEXT call bcopy_4
and SCBARRAY+0,0xef,SCBARRAY+0
test SG_NOLOAD,0x80 jz sg_ram2scb1 # reload s/g?
or SCBARRAY+0,SG_LOAD
sg_ram2scb1:
ret
# Load a struct scatter if needed 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 the above DMA, assumes a little-endian host data storage.
#
sg_load:
test SG_COUNT,0xff jz sg_load3 # SG being used?
test SG_NOLOAD,0x80 jnz sg_load3 # don't reload s/g?
clr HCNT+2
clr HCNT+1
mvi HCNT+0,SG_SIZEOF
mvi DINDEX,HADDR
mvi SG_NEXT call bcopy_4
mvi DFCNTRL,0xd # HDMAEN|DIRECTION|FIFORESET
# Wait for DMA from host memory to data FIFO to complete, then disable
# DMA and wait for it to acknowledge that it's off.
#
sg_load1:
test DFSTATUS,0x8 jz sg_load1 # HDONE
clr DFCNTRL # disable DMA
sg_load2:
test DFCNTRL,0x8 jnz sg_load2 # HDMAENACK
# Copy data from FIFO into SCB data pointer and data count. This assumes
# that the struct scatterlist has this structure (this and sizeof(struct
# scatterlist) == 12 are asserted in aic7xxx.c):
#
# struct scatterlist {
# char *address; /* four bytes, little-endian order */
# ... /* four bytes, ignored */
# unsigned short length; /* two bytes, little-endian order */
# }
#
# Not in FreeBSD. the scatter list is only 8 bytes.
#
# struct ahc_dma_seg {
# physaddr addr; /* four bytes, little-endian order */
# long len; /* four bytes, little endian order */
# };
#
mov SCBARRAY+19,DFDAT # new data address
mov SCBARRAY+20,DFDAT
mov SCBARRAY+21,DFDAT
mov SCBARRAY+22,DFDAT
# For Linux, we must throw away four bytes since there is a 32bit gap
# in the middle of a struct scatterlist
# mov NONE,DFDAT
# mov NONE,DFDAT
# mov NONE,DFDAT
# mov NONE,DFDAT
mov SCBARRAY+23,DFDAT
mov SCBARRAY+24,DFDAT
mov SCBARRAY+25,DFDAT #Only support 24 bit length.
sg_load3:
ret
# Advance the scatter-gather pointers only IF NEEDED. If SG is enabled,
# and the SCSI transfer count is zero (note that this should be called
# right after a DMA finishes), then move the working copies of the SG
# pointer/length along. If the SCSI transfer count is not zero, then
# presumably the target is disconnecting - do not reload the SG values
# next time.
#
sg_advance:
test SG_COUNT,0xff jz sg_advance2 # s/g enabled?
test STCNT+0,0xff jnz sg_advance1 # SCSI transfer count nonzero?
test STCNT+1,0xff jnz sg_advance1
test STCNT+2,0xff jnz sg_advance1
clr SG_NOLOAD # reload s/g next time
dec SG_COUNT # one less segment to go
clr A # add sizeof(struct scatter)
add SG_NEXT+0,SG_SIZEOF,SG_NEXT+0
adc SG_NEXT+1,A,SG_NEXT+1
adc SG_NEXT+2,A,SG_NEXT+2
adc SG_NEXT+3,A,SG_NEXT+3 ret
sg_advance1:
mvi SG_NOLOAD,0x80 # don't reload s/g next time
sg_advance2:
ret
# Add the array base SYNCNEG to the target offset (the target address
# is in SCSIID), and return the result in SINDEX. The accumulator
# contains the 3->8 decoding of the target ID on return.
#
ndx_dtr:
shr A,SCSIID,4
test SBLKCTL,0x08 jz ndx_dtr_2
or A,0x08 # Channel B entries add 8
ndx_dtr_2:
add SINDEX,SYNCNEG,A
and FUNCTION1,0x70,SCSIID # 3-bit target address decode
mov A,FUNCTION1 ret
# If we need to negotiate transfer parameters, build the WDTR or SDTR message
# starting at the address passed in SINDEX. DINDEX is modified on return.
# The SCSI-II spec requires that Wide negotiation occur first and you can
# only negotiat one or the other at a time otherwise in the event of a message
# reject, you wouldn't be able to tell which message was the culpret.
#
mk_dtr:
mov DINDEX,SINDEX # save SINDEX
test SCBARRAY+0,NEEDWDTR jnz mk_wdtr_16bit
jmp mk_sdtr
mk_wdtr_16bit:
mvi ARG_1,BUS_16_BIT
mk_wdtr:
mvi DINDIR,1 # extended message
mvi DINDIR,2 # extended message length = 2
mvi DINDIR,3 # WDTR code
mov DINDIR,ARG_1 # bus width
add MSG_LEN,-MSG_START+0,DINDEX ret # update message length
mk_sdtr:
mvi DINDIR,1 # extended message
mvi DINDIR,3 # extended message length = 3
mvi DINDIR,1 # SDTR code
call sdtr_to_rate
mov DINDIR,RETURN_1 # REQ/ACK transfer period
and DINDIR,0xf,SINDIR # Sync Offset
add MSG_LEN,-MSG_START+0,DINDEX ret # update message length
# Set SCSI bus control signal state. This also saves the last-written
# value into a location where the higher-level driver can read it - if
# it has to send an ABORT or RESET message, then it needs to know this
# so it can assert ATN without upsetting SCSISIGO. The new value is
# expected in SINDEX. Change the actual state last to avoid contention
# from the driver.
#
scsisig:
mov SIGSTATE,SINDEX
mov SCSISIGO,SINDEX ret
sdtr_to_rate:
call ndx_dtr # index scratch space for target
shr A,SINDIR,0x4
dec SINDEX #Preserve SINDEX
and A,0x7
clr RETURN_1
sdtr_to_rate_loop:
test A,0x0f jz sdtr_to_rate_done
add RETURN_1,0x18
dec A
jmp sdtr_to_rate_loop
sdtr_to_rate_done:
shr RETURN_1,0x2
add RETURN_1,0x18 ret
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