diff options
Diffstat (limited to 'sys/dev')
| -rw-r--r-- | sys/dev/aic7xxx/aic7xxx.seq | 199 |
1 files changed, 104 insertions, 95 deletions
diff --git a/sys/dev/aic7xxx/aic7xxx.seq b/sys/dev/aic7xxx/aic7xxx.seq index 435da74..c5a1e9b 100644 --- a/sys/dev/aic7xxx/aic7xxx.seq +++ b/sys/dev/aic7xxx/aic7xxx.seq @@ -41,11 +41,12 @@ # ##-M######################################################################### -VERSION AIC7XXX_SEQ_VER "$Id: aic7xxx.seq,v 1.13 1995/04/09 06:40:16 gibbs Exp $" +VERSION AIC7XXX_SEQ_VER "$Id: aic7xxx.seq,v 1.14 1995/04/15 21:45:56 gibbs Exp $" SCBMASK = 0x1f SCSISEQ = 0x00 +ENRSELI = 0x10 SXFRCTL0 = 0x01 SXFRCTL1 = 0x02 SCSISIGI = 0x03 @@ -57,7 +58,10 @@ STCNT = 0x08 STCNT+0 = 0x08 STCNT+1 = 0x09 STCNT+2 = 0x0a +CLRSINT0 = 0x0b SSTAT0 = 0x0b +SELDO = 0x40 +SELDI = 0x20 CLRSINT1 = 0x0c SSTAT1 = 0x0c SIMODE1 = 0x11 @@ -138,9 +142,10 @@ SCBARRAY+26 = 0xba SCBARRAY+27 = 0xbb SCBARRAY+28 = 0xbc SCBARRAY+29 = 0xbd +SCBARRAY+30 = 0xbe BAD_PHASE = 0x01 # unknown scsi bus phase -CMDCMPLT = 0x02 +CMDCMPLT = 0x02 # Command Complete SEND_REJECT = 0x11 # sending a message reject NO_IDENT = 0x21 # no IDENTIFY after reconnect NO_MATCH = 0x31 # no cmd match for reconnect @@ -164,23 +169,23 @@ ABORT_TAG = 0x91 # Sent an ABORT_TAG message # 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. +# 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. +# 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. # # Note that SG_NEXT occupies four bytes. # SYNCNEG = 0x20 -DROPATN = 0x30 REJBYTE = 0x31 DISC_DSB_A = 0x32 DISC_DSB_B = 0x33 @@ -218,49 +223,77 @@ FLAGS = 0x53 # Device configuration flags TWIN_BUS = 0x01 WIDE_BUS = 0x02 MAX_SYNC = 0x08 -SENSE = 0x10 ACTIVE_MSG = 0x20 IDENTIFY_SEEN = 0x40 RESELECTED = 0x80 ACTIVE_A = 0x54 ACTIVE_B = 0x55 -SAVED_TCL = 0x56 +SAVED_TCL = 0x56 # Temporary storage for the + # target/channel/lun of a + # reconnecting target + +# After starting the selection hardware, we return to the "poll_for_work" +# loop so that we can 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 31 of the SCB as a psuedo-next pointer and to thread a list +# of SCBs that are awaiting selection. Since 0 is a valid SCB offset, +# SCB_LIST_NULL is 0x10 which is out of range. The kernel driver must +# add an entry to this list everytime a request sense occurs. The sequencer +# will automatically consume the entries. + +WAITING_SCBH = 0x57 # head of list of SCBs awaiting + # selection +WAITING_SCBT = 0x58 # tail of list of SCBs awaiting + # selection +SCB_LIST_NULL = 0x10 + + # 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 WAITING_SCBH,SCB_LIST_NULL jz start_waiting +poll_for_work: 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 + test SSTAT0,SELDI jnz reselect + test SSTAT0,SELDO jnz select xor SBLKCTL,0x08 # Toggle to the original bus start2: - test SCSISIGI,0x4 jnz reselect # BSYI - test QINCNT,SCBMASK jz start_nosense + test SSTAT0,SELDI jnz reselect + test SSTAT0,SELDO jnz select + test WAITING_SCBH,SCB_LIST_NULL jz start_waiting + test QINCNT,SCBMASK jz poll_for_work -# 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. +# We have at least one queued SCB now and we don't have any +# SCBs in the list of SCBs awaiting selection. 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 +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 + 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. @@ -270,12 +303,12 @@ test SCBARRAY+0,NEEDDMA jz test_busy # Copy the SCB from the FIFO to the SCBARRAY mvi DINDEX, SCBARRAY+0 - call bcopy_3_dfdat - call bcopy_4_dfdat + call bcopy_3_dfdat call bcopy_4_dfdat call bcopy_4_dfdat + call bcopy_4_dfdat call bcopy_4_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 @@ -295,27 +328,35 @@ test_busy: 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 + jmp poll_for_work + +# Pull the first entry off of the waiting for selection list +start_waiting: + mov SCBPTR,WAITING_SCBH + jmp start_scb 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,0xf7,SBLKCTL #Clear the channel select bit and A,0x08,SCBARRAY+1 #Get new channel bit or SINDEX,A mov SBLKCTL,SINDEX # select channel - mov SCBARRAY+1 call initialize + mov SCBARRAY+1 call initialize_scsiid + +# Enable selection phase as an initiator, and do automatic ATN +# after the selection. We do this now so that we can overlap the +# rest of our work to set up this target with the arbitration and +# selection bus phases. +# +start_selection: + or SCSISEQ,0x48 # ENSELO|ENAUTOATNO + mov WAITING_SCBH, SCBPTR clr SG_NOLOAD and FLAGS,0x3f # !RESELECTING @@ -355,61 +396,30 @@ mk_tag_done: mov DINDEX call mk_dtr # build DTR message if needed !message: + jmp poll_for_work -# 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 +# 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. # reselect: - mvi SCSISEQ,0x10 # ENRSELI - -reselect1: - test SSTAT0,0x20 jz reselect1 # SELDI - mov SELID call initialize - + mov SELID call initialize_scsiid and FLAGS,0x3f # reselected, no IDENTIFY - or FLAGS,RESELECTED + or FLAGS,RESELECTED jmp select2 -# 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. +# After the selection, remove this SCB from the "waiting for selection" +# list. This is achieved by simply moving our "next" pointer into +# WAITING_SCBH and setting our next pointer to null so that the next +# time this SCB is used, we don't get confused. # -*select: - clr SCSISEQ +select: + or SCBARRAY+0,NEEDDMA + mov WAITING_SCBH,SCBARRAY+30 + mvi SCBARRAY+30,SCB_LIST_NULL +select2: + call initialize_for_target + mvi SCSISEQ,ENRSELI + mvi CLRSINT0,0x60 # CLRSELDI|CLRSELDO mvi CLRSINT1,0x8 # CLRBUSFREE # Main loop for information transfer phases. If BSY is false, then @@ -636,11 +646,12 @@ p_mesgin: # 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 set the SENSE sequencer flag. If the sense flag is -# set, the sequencer imediately jumps to start working on the sense -# command. If the kernel driver does not wish to request sense, it need -# do nothing, and the command is allowed to complete. We don't +# the driver will download a new scb requesting sense to replace +# the old one, modify the "waiting for selection" SCB list and set +# RETURN_1 to 0x80. If RETURN_1 is set to 0x80 the sequencer imediately +# jumps to main loop where it will run down the waiting SCB list. +# If the kernel driver does not wish to request sense, it need +# only clear RETURN_1, 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. @@ -653,7 +664,7 @@ p_mesgin: check_status: test SCBARRAY+14,0xff jz status_ok # 0 Status? mvi INTSTAT,BAD_STATUS # let driver know - test FLAGS,SENSE jz status_ok + test RETURN_1, 0x80 jz status_ok jmp p_mesgin_done status_ok: @@ -977,23 +988,21 @@ dma_finish2: # the target SCSI ID to be in the upper four bits of SINDEX, and A's # contents are stomped on return. # -initialize: +initialize_scsiid: and SINDEX,0xf0 # Get target ID and A,0x0f,SCSIID or SINDEX,A - mov SCSIID,SINDEX - -# Esundry initialization. -# - clr DROPATN - clr SIGSTATE + mov SCSIID,SINDEX ret +initialize_for_target: # 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. # + clr SIGSTATE + mvi SXFRCTL0,0x8a # DFON|SPIOEN|CLRCHN # Initialize scatter-gather pointers by setting up the working copy |
