aic7xxx.seq revision 9928
1##+M######################################################################### 2# Adaptec 274x/284x/294x device driver for Linux and FreeBSD. 3# 4# Copyright (c) 1994 John Aycock 5# The University of Calgary Department of Computer Science. 6# All rights reserved. 7# 8# Modifications/enhancements: 9# Copyright (c) 1994, 1995 Justin Gibbs. All rights reserved. 10# 11# Redistribution and use in source and binary forms, with or without 12# modification, are permitted provided that the following conditions 13# are met: 14# 1. Redistributions of source code must retain the above copyright 15# notice, this list of conditions, and the following disclaimer. 16# 2. Redistributions in binary form must reproduce the above copyright 17# notice, this list of conditions and the following disclaimer in the 18# documentation and/or other materials provided with the distribution. 19# 3. All advertising materials mentioning features or use of this software 20# must display the following acknowledgement: 21# This product includes software developed by the University of Calgary 22# Department of Computer Science and its contributors. 23# 4. Neither the name of the University nor the names of its contributors 24# may be used to endorse or promote products derived from this software 25# without specific prior written permission. 26# 27# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 28# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 31# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37# SUCH DAMAGE. 38# 39# FreeBSD, Twin, Wide, 2 command per target support, tagged queuing and other 40# optimizations provided by Justin T. Gibbs (gibbs@FreeBSD.org) 41# 42##-M######################################################################### 43 44VERSION AIC7XXX_SEQ_VER "$Id: aic7xxx.seq,v 1.18 1995/07/31 08:21:59 gibbs Exp $" 45 46SCBMASK = 0xff 47 48SCSISEQ = 0x00 49ENRSELI = 0x10 50SXFRCTL0 = 0x01 51SXFRCTL1 = 0x02 52SCSISIGI = 0x03 53SCSISIGO = 0x03 54SCSIRATE = 0x04 55SCSIID = 0x05 56SCSIDATL = 0x06 57STCNT = 0x08 58STCNT+0 = 0x08 59STCNT+1 = 0x09 60STCNT+2 = 0x0a 61CLRSINT0 = 0x0b 62SSTAT0 = 0x0b 63SELDO = 0x40 64SELDI = 0x20 65CLRSINT1 = 0x0c 66SSTAT1 = 0x0c 67PHASEMIS = 0x10 68SIMODE1 = 0x11 69SCSIBUSL = 0x12 70SHADDR = 0x14 71SELID = 0x19 72SBLKCTL = 0x1f 73SEQCTL = 0x60 74A = 0x64 # == ACCUM 75SINDEX = 0x65 76DINDEX = 0x66 77ALLZEROS = 0x6a 78NONE = 0x6a 79SINDIR = 0x6c 80DINDIR = 0x6d 81FUNCTION1 = 0x6e 82HADDR = 0x88 83HADDR+1 = 0x89 84HADDR+2 = 0x8a 85HADDR+3 = 0x8b 86HCNT = 0x8c 87HCNT+0 = 0x8c 88HCNT+1 = 0x8d 89HCNT+2 = 0x8e 90SCBPTR = 0x90 91INTSTAT = 0x91 92DFCNTRL = 0x93 93DFSTATUS = 0x94 94DFDAT = 0x99 95QINFIFO = 0x9b 96QINCNT = 0x9c 97QOUTFIFO = 0x9d 98 99SCSICONF_A = 0x5a 100SCSICONF_B = 0x5b 101 102# The two reserved bytes at SCBARRAY+1[23] are expected to be set to 103# zero. Bit 3 in SCBARRAY+0 is used as an internal flag to indicate 104# whether or not to DMA an SCB from host ram. This flag prevents the 105# "re-fetching" of transactions that are requed because the target is 106# busy with another command. We also use bits 6 & 7 to indicate whether 107# or not to initiate SDTR or WDTR repectively when starting this command. 108# 109SCBARRAY+0 = 0xa0 110 111DISCONNECTED = 0x04 112NEEDDMA = 0x08 113NEEDSDTR = 0x10 114TAG_ENB = 0x20 115DISCENB = 0x40 116NEEDWDTR = 0x80 117 118SCBARRAY+1 = 0xa1 119SCBARRAY+2 = 0xa2 120SCBARRAY+3 = 0xa3 121SCBARRAY+4 = 0xa4 122SCBARRAY+5 = 0xa5 123SCBARRAY+6 = 0xa6 124SCBARRAY+7 = 0xa7 125SCBARRAY+8 = 0xa8 126SCBARRAY+9 = 0xa9 127SCBARRAY+10 = 0xaa 128SCBARRAY+11 = 0xab 129SCBARRAY+12 = 0xac 130SCBARRAY+13 = 0xad 131SCBARRAY+14 = 0xae 132SCBARRAY+15 = 0xaf 133SCBARRAY+16 = 0xb0 134SCBARRAY+17 = 0xb1 135SCBARRAY+18 = 0xb2 136SCBARRAY+19 = 0xb3 137SCBARRAY+20 = 0xb4 138SCBARRAY+21 = 0xb5 139SCBARRAY+22 = 0xb6 140SCBARRAY+23 = 0xb7 141SCBARRAY+24 = 0xb8 142SCBARRAY+25 = 0xb9 143SCBARRAY+26 = 0xba 144SCBARRAY+27 = 0xbb 145SCBARRAY+28 = 0xbc 146SCBARRAY+29 = 0xbd 147SCBARRAY+30 = 0xbe 148 149BAD_PHASE = 0x01 # unknown scsi bus phase 150CMDCMPLT = 0x02 # Command Complete 151SEND_REJECT = 0x11 # sending a message reject 152NO_IDENT = 0x21 # no IDENTIFY after reconnect 153NO_MATCH = 0x31 # no cmd match for reconnect 154MSG_SDTR = 0x41 # SDTR message recieved 155MSG_WDTR = 0x51 # WDTR message recieved 156MSG_REJECT = 0x61 # Reject message recieved 157BAD_STATUS = 0x71 # Bad status from target 158RESIDUAL = 0x81 # Residual byte count != 0 159ABORT_TAG = 0x91 # Sent an ABORT_TAG message 160AWAITING_MSG = 0xa1 # Kernel requested to specify 161 # a message to this target 162 # (command was null), so tell 163 # it that it can fill the 164 # message buffer. 165IMMEDDONE = 0xb1 166 167 168# The host adapter card (at least the BIOS) uses 20-2f for SCSI 169# device information, 32-33 and 5a-5f as well. As it turns out, the 170# BIOS trashes 20-2f, writing the synchronous negotiation results 171# on top of the BIOS values, so we re-use those for our per-target 172# scratchspace (actually a value that can be copied directly into 173# SCSIRATE). The kernel driver will enable synchronous negotiation 174# for all targets that have a value other than 0 in the lower four 175# bits of the target scratch space. This should work regardless of 176# whether the bios has been installed. NEEDSDTR and NEEDWDTR are the 177# fouth and sevent bits of the SCB control byte. The kernel driver 178# will set these when a WDTR or SDTR message should be sent to the 179# target the SCB's command references. 180# 181# REJBYTE contains the first byte of a MESSAGE IN message, so the driver 182# can report an intelligible error if a message is rejected. 183# 184# FLAGS's high bit is true if we are currently handling a reselect; 185# its next-highest bit is true ONLY IF we've seen an IDENTIFY message 186# from the reselecting target. If we haven't had IDENTIFY, then we have 187# no idea what the lun is, and we can't select the right SCB register 188# bank, so force a kernel panic if the target attempts a data in/out or 189# command phase instead of corrupting something. FLAGS also contains 190# configuration bits so that we can optimize for TWIN and WIDE controllers, 191# the MAX_OFFSET bit which we set when we want to negotiate for maximum sync 192# offset irregardless of what the per target scratch space says. 193# 194# Note that SG_NEXT occupies four bytes. 195# 196SYNCNEG = 0x20 197 198REJBYTE = 0x31 199DISC_DSB_A = 0x32 200DISC_DSB_B = 0x33 201 202MSG_LEN = 0x34 203MSG_START+0 = 0x35 204MSG_START+1 = 0x36 205MSG_START+2 = 0x37 206MSG_START+3 = 0x38 207MSG_START+4 = 0x39 208MSG_START+5 = 0x3a 209-MSG_START+0 = 0xcb # 2's complement of MSG_START+0 210 211ARG_1 = 0x4a # sdtr conversion args & return 212BUS_16_BIT = 0x01 213RETURN_1 = 0x4a 214 215SIGSTATE = 0x4b # value written to SCSISIGO 216 217# Linux users should use 0xc (12) for SG_SIZEOF 218SG_SIZEOF = 0x8 # sizeof(struct ahc_dma) 219#SG_SIZEOF = 0xc # sizeof(struct scatterlist) 220SCB_SIZEOF = 0x1a # sizeof SCB to DMA (26 bytes) 221 222DMAPARAMS = 0x4c # Parameters for DMA 223SG_COUNT = 0x4d # working value of SG count 224SG_NEXT = 0x4e # working value of SG pointer 225SG_NEXT+0 = 0x4e 226SG_NEXT+1 = 0x4f 227SG_NEXT+2 = 0x50 228SG_NEXT+3 = 0x51 229 230SCBCOUNT = 0x52 # the actual number of SCBs 231FLAGS = 0x53 # Device configuration flags 232TWIN_BUS = 0x01 233WIDE_BUS = 0x02 234DPHASE = 0x04 235MAX_OFFSET = 0x08 236ACTIVE_MSG = 0x20 237IDENTIFY_SEEN = 0x40 238RESELECTED = 0x80 239 240MAX_OFFSET_8BIT = 0x0f 241MAX_OFFSET_WIDE = 0x08 242 243ACTIVE_A = 0x54 244ACTIVE_B = 0x55 245SAVED_TCL = 0x56 # Temporary storage for the 246 # target/channel/lun of a 247 # reconnecting target 248# After starting the selection hardware, we return to the "poll_for_work" 249# loop so that we can check for reconnecting targets as well as for our 250# selection to complete just in case the reselection wins bus arbitration. 251# The problem with this is that we must keep track of the SCB that we've 252# already pulled from the QINFIFO and started the selection on just in case 253# the reselection wins so that we can retry the selection at a later time. 254# This problem cannot be resolved by holding a single entry in scratch 255# ram since a reconnecting target can request sense and this will create 256# yet another SCB waiting for selection. The solution used here is to 257# use byte 31 of the SCB as a psuedo-next pointer and to thread a list 258# of SCBs that are awaiting selection. Since 0-0xfe are valid SCB offsets, 259# SCB_LIST_NULL is 0xff which is out of range. The kernel driver must 260# add an entry to this list everytime a request sense occurs. The sequencer 261# will automatically consume the entries. 262 263WAITING_SCBH = 0x57 # head of list of SCBs awaiting 264 # selection 265WAITING_SCBT = 0x58 # tail of list of SCBs awaiting 266 # selection 267SCB_LIST_NULL = 0xff 268 269 270# Poll QINCNT for work - the lower bits contain 271# the number of entries in the Queue In FIFO. 272# 273poll_for_work: 274 test FLAGS,TWIN_BUS jz start2 # Are we a twin channel device? 275# For fairness, we check the other bus first, since we just finished a 276# transaction on the current channel. 277 xor SBLKCTL,0x08 # Toggle to the other bus 278 test SSTAT0,SELDI jnz reselect 279 xor SBLKCTL,0x08 # Toggle to the original bus 280start2: 281 test SSTAT0,SELDI jnz reselect 282 cmp WAITING_SCBH,SCB_LIST_NULL jne start_waiting 283 test QINCNT,SCBMASK jz poll_for_work 284 285# We have at least one queued SCB now and we don't have any 286# SCBs in the list of SCBs awaiting selection. Set the SCB 287# pointer from the FIFO so we see the right bank of SCB 288# registers, then set SCSI options and set the initiator and 289# target SCSI IDs. 290# 291 mov SCBPTR,QINFIFO 292 293# If the control byte of this SCB has the NEEDDMA flag set, we have 294# yet to DMA it from host memory 295 296test SCBARRAY+0,NEEDDMA jz test_busy 297 clr HCNT+2 298 clr HCNT+1 299 mvi HCNT+0,SCB_SIZEOF 300 301 mvi DINDEX,HADDR 302 mvi SCBARRAY+26 call bcopy_4 303 304 mvi DFCNTRL,0xd # HDMAEN|DIRECTION|FIFORESET 305 306# Wait for DMA from host memory to data FIFO to complete, then disable 307# DMA and wait for it to acknowledge that it's off. 308# 309 call dma_finish 310 311# Copy the SCB from the FIFO to the SCBARRAY 312 313 mvi DINDEX, SCBARRAY+0 314 call bcopy_5_dfdat 315 call bcopy_7_dfdat 316 call bcopy_7_dfdat 317 call bcopy_7_dfdat 318 319# See if there is not already an active SCB for this target. This code 320# locks out on a per target basis instead of target/lun. Although this 321# is not ideal for devices that have multiple luns active at the same 322# time, it is faster than looping through all SCB's looking for active 323# commands. It may be benificial to make findscb a more general procedure 324# to see if the added cost of the search is negligible. This code also 325# assumes that the kernel driver will clear the active flags on board 326# initialization, board reset, and a target's SELTO. 327 328test_busy: 329 and FUNCTION1,0x70,SCBARRAY+1 330 mov A,FUNCTION1 331 test SCBARRAY+1,0x88 jz test_a # Id < 8 && A channel 332 333 test ACTIVE_B,A jnz requeue 334 test SCBARRAY+0,TAG_ENB jnz start_scb 335 or ACTIVE_B,A # Mark the current target as busy 336 jmp start_scb 337 338# Place the currently active back on the queue for later processing 339requeue: 340 mov QINFIFO, SCBPTR 341 jmp poll_for_work 342 343# Pull the first entry off of the waiting for selection list 344start_waiting: 345 mov SCBPTR,WAITING_SCBH 346 jmp start_scb 347 348test_a: 349 test ACTIVE_A,A jnz requeue 350 test SCBARRAY+0,TAG_ENB jnz start_scb 351 or ACTIVE_A,A # Mark the current target as busy 352 353start_scb: 354 and SINDEX,0xf7,SBLKCTL #Clear the channel select bit 355 and A,0x08,SCBARRAY+1 #Get new channel bit 356 or SINDEX,A 357 mov SBLKCTL,SINDEX # select channel 358 mov SCBARRAY+1 call initialize_scsiid 359 360# Enable selection phase as an initiator, and do automatic ATN 361# after the selection. We do this now so that we can overlap the 362# rest of our work to set up this target with the arbitration and 363# selection bus phases. 364# 365start_selection: 366 or SCSISEQ,0x48 # ENSELO|ENAUTOATNO 367 mov WAITING_SCBH, SCBPTR 368 and FLAGS,0x3f # !RESELECTING 369 370# As soon as we get a successful selection, the target should go 371# into the message out phase since we have ATN asserted. Prepare 372# the message to send, locking out the device driver. If the device 373# driver hasn't beaten us with an ABORT or RESET message, then tack 374# on an SDTR negotiation if required. 375# 376# Messages are stored in scratch RAM starting with a flag byte (high bit 377# set means active message), one length byte, and then the message itself. 378# 379 380 test SCBARRAY+11,0xff jnz identify # 0 Length Command? 381 382# The kernel has sent us an SCB with no command attached. This implies 383# that the kernel wants to send a message of some sort to this target, 384# so we interrupt the driver, allow it to fill the message buffer, and 385# then go back into the arbitration loop 386 mvi INTSTAT,AWAITING_MSG 387 jmp wait_for_selection 388 389identify: 390 and A,DISCENB,SCBARRAY+0 # mask off disconnect privledge 391 392 and SINDEX,0x7,SCBARRAY+1 # lun 393 or SINDEX,A # or in disconnect privledge 394 or SINDEX,0x80 call mk_mesg # IDENTIFY message 395 396 mov A,SINDEX 397 test SCBARRAY+0,0xb0 jz !message # WDTR, SDTR or TAG?? 398 cmp MSG_START+0,A jne !message # did driver beat us? 399 400# Tag Message if Tag enabled in SCB control block. Use SCBPTR as the tag 401# value 402 403mk_tag: 404 mvi DINDEX, MSG_START+1 405 test SCBARRAY+0,TAG_ENB jz mk_tag_done 406 and A,0x23,SCBARRAY+0 407 mov DINDIR,A 408 mov DINDIR,SCBPTR 409 410 add MSG_LEN,-MSG_START+0,DINDEX # update message length 411 412mk_tag_done: 413 414 mov DINDEX call mk_dtr # build DTR message if needed 415 416!message: 417wait_for_selection: 418 test SSTAT0,SELDI jnz reselect 419 test SSTAT0,SELDO jnz select 420 jmp wait_for_selection 421 422# Reselection has been initiated by a target. Make a note that we've been 423# reselected, but haven't seen an IDENTIFY message from the target 424# yet. 425# 426reselect: 427 mov SELID call initialize_scsiid 428 and FLAGS,0x3f # reselected, no IDENTIFY 429 or FLAGS,RESELECTED jmp select2 430 431# After the selection, remove this SCB from the "waiting for selection" 432# list. This is achieved by simply moving our "next" pointer into 433# WAITING_SCBH and setting our next pointer to null so that the next 434# time this SCB is used, we don't get confused. 435# 436select: 437 or SCBARRAY+0,NEEDDMA 438 mov WAITING_SCBH,SCBARRAY+30 439 mvi SCBARRAY+30,SCB_LIST_NULL 440select2: 441 call initialize_for_target 442 mvi SCSISEQ,ENRSELI 443 mvi CLRSINT0,0x60 # CLRSELDI|CLRSELDO 444 mvi CLRSINT1,0x8 # CLRBUSFREE 445 446# Main loop for information transfer phases. If BSY is false, then 447# we have a bus free condition, expected or not. Otherwise, wait 448# for the target to assert REQ before checking MSG, C/D and I/O 449# for the bus phase. 450# 451# We can't simply look at the values of SCSISIGI here (if we want 452# to do synchronous data transfer), because the target won't assert 453# REQ if it's already sent us some data that we haven't acknowledged 454# yet. 455# 456ITloop: 457 test SSTAT1,0x8 jnz p_busfree # BUSFREE 458 test SSTAT1,0x1 jz ITloop # REQINIT 459 460 and A,0xe0,SCSISIGI # CDI|IOI|MSGI 461 462 cmp ALLZEROS,A je p_dataout 463 cmp A,0x40 je p_datain 464 cmp A,0x80 je p_command 465 cmp A,0xc0 je p_status 466 cmp A,0xa0 je p_mesgout 467 cmp A,0xe0 je p_mesgin 468 469 mvi INTSTAT,BAD_PHASE # unknown - signal driver 470 471p_dataout: 472 mvi 0 call scsisig # !CDO|!IOO|!MSGO 473 mvi DMAPARAMS,0x7d # WIDEODD|SCSIEN|SDMAEN|HDMAEN| 474 # DIRECTION|FIFORESET 475 jmp data_phase_init 476 477# If we re-enter the data phase after going through another phase, the 478# STCNT may have been cleared, so restore it from the residual field. 479data_phase_reinit: 480 mvi DINDEX, STCNT 481 mvi SCBARRAY+15 call bcopy_3 482 jmp data_phase_loop 483 484# Reads should not use WIDEODD since it may make the last byte for a SG segment 485# go to the next segment. 486p_datain: 487 mvi 0x40 call scsisig # !CDO|IOO|!MSGO 488 mvi DMAPARAMS,0x39 # SCSIEN|SDMAEN|HDMAEN| 489 # !DIRECTION|FIFORESET 490data_phase_init: 491 call assert 492 493 test FLAGS, DPHASE jnz data_phase_reinit 494 call sg_scb2ram 495 or FLAGS, DPHASE # We have seen a data phase 496 497data_phase_loop: 498# If we are the last SG block, don't set wideodd. 499 cmp SG_COUNT,0x01 jne data_phase_wideodd 500 and DMAPARAMS, 0xbf # Turn off WIDEODD 501data_phase_wideodd: 502 mov DMAPARAMS call dma 503 504# Exit if we had an underrun 505 test SSTAT0,0x04 jz data_phase_finish # underrun STCNT != 0 506 507# Advance the scatter-gather pointers if needed 508# 509sg_advance: 510 dec SG_COUNT # one less segment to go 511 512 test SG_COUNT, 0xff jz data_phase_finish #Are we done? 513 514 clr A # add sizeof(struct scatter) 515 add SG_NEXT+0,SG_SIZEOF,SG_NEXT+0 516 adc SG_NEXT+1,A,SG_NEXT+1 517 adc SG_NEXT+2,A,SG_NEXT+2 518 adc SG_NEXT+3,A,SG_NEXT+3 519 520# Load a struct scatter and set up the data address and length. 521# If the working value of the SG count is nonzero, then 522# we need to load a new set of values. 523# 524# This, like all DMA's, assumes a little-endian host data storage. 525# 526sg_load: 527 clr HCNT+2 528 clr HCNT+1 529 mvi HCNT+0,SG_SIZEOF 530 531 mvi DINDEX,HADDR 532 mvi SG_NEXT call bcopy_4 533 534 mvi DFCNTRL,0xd # HDMAEN|DIRECTION|FIFORESET 535 536# Wait for DMA from host memory to data FIFO to complete, then disable 537# DMA and wait for it to acknowledge that it's off. 538# 539 call dma_finish 540 541# Copy data from FIFO into SCB data pointer and data count. This assumes 542# that the struct scatterlist has this structure (this and sizeof(struct 543# scatterlist) == 12 are asserted in aic7xxx.c): 544# 545# struct scatterlist { 546# char *address; /* four bytes, little-endian order */ 547# ... /* four bytes, ignored */ 548# unsigned short length; /* two bytes, little-endian order */ 549# } 550# 551 552# Not in FreeBSD. the scatter list entry is only 8 bytes. 553# 554# struct ahc_dma_seg { 555# physaddr addr; /* four bytes, little-endian order */ 556# long len; /* four bytes, little endian order */ 557# }; 558# 559 560 mvi DINDEX,HADDR 561 call bcopy_7_dfdat 562 563# For Linux, we must throw away four bytes since there is a 32bit gap 564# in the middle of a struct scatterlist 565# call bcopy_4_dfdat 566# mov NONE,DFDAT 567# mov NONE,DFDAT 568# mov NONE,DFDAT 569# mov NONE,DFDAT 570# call bcopy_3_dfdat #Only support 24 bit length. 571 572# Load STCNT as well. It is a mirror of HCNT 573 mvi DINDEX,STCNT 574 mvi HCNT call bcopy_3 575 test SSTAT1,PHASEMIS jz data_phase_loop 576 577data_phase_finish: 578# After a DMA finishes, save the SG and STCNT residuals back into the SCB 579# We use STCNT instead of HCNT, since it's a reflection of how many bytes 580# were transferred on the SCSI (as opposed to the host) bus. 581# 582 mvi DINDEX,SCBARRAY+15 583 mvi STCNT call bcopy_3 584 mov SCBARRAY+18, SG_COUNT 585 jmp ITloop 586 587# Command phase. Set up the DMA registers and let 'er rip - the 588# two bytes after the SCB SCSI_cmd_length are zeroed by the driver, 589# so we can copy those three bytes directly into HCNT. 590# 591p_command: 592 mvi 0x80 call scsisig # CDO|!IOO|!MSGO 593 call assert 594 595# Load HADDR and HCNT. We can do this in one bcopy since they are neighbors 596 mvi DINDEX,HADDR 597 mvi SCBARRAY+7 call bcopy_7 598 599 mvi DINDEX,STCNT 600 mvi SCBARRAY+11 call bcopy_3 601 602 mvi 0x3d call dma # SCSIEN|SDMAEN|HDMAEN| 603 # DIRECTION|FIFORESET 604 jmp ITloop 605 606# Status phase. Wait for the data byte to appear, then read it 607# and store it into the SCB. 608# 609p_status: 610 mvi 0xc0 call scsisig # CDO|IOO|!MSGO 611 612 mvi SCBARRAY+14 call inb_first 613 jmp p_mesgin_done 614 615# Message out phase. If there is no active message, but the target 616# took us into this phase anyway, build a no-op message and send it. 617# 618p_mesgout: 619 mvi 0xa0 call scsisig # CDO|!IOO|MSGO 620 mvi 0x8 call mk_mesg # build NOP message 621 622 clr STCNT+2 623 clr STCNT+1 624 625# Set up automatic PIO transfer from MSG_START. Bit 3 in 626# SXFRCTL0 (SPIOEN) is already on. 627# 628 mvi SINDEX,MSG_START+0 629 mov DINDEX,MSG_LEN 630 631# When target asks for a byte, drop ATN if it's the last one in 632# the message. Otherwise, keep going until the message is exhausted. 633# (We can't use outb for this since it wants the input in SINDEX.) 634# 635# Keep an eye out for a phase change, in case the target issues 636# a MESSAGE REJECT. 637# 638p_mesgout2: 639 test SSTAT0,0x2 jz p_mesgout2 # SPIORDY 640 test SSTAT1,0x10 jnz p_mesgout6 # PHASEMIS 641 642 cmp DINDEX,1 jne p_mesgout3 # last byte? 643 mvi CLRSINT1,0x40 # CLRATNO - drop ATN 644 645# Write a byte to the SCSI bus. The AIC-7770 refuses to automatically 646# send ACKs in automatic PIO or DMA mode unless you make sure that the 647# "expected" bus phase in SCSISIGO matches the actual bus phase. This 648# behaviour is completely undocumented and caused me several days of 649# grief. 650# 651# After plugging in different drives to test with and using a longer 652# SCSI cable, I found that I/O in Automatic PIO mode ceased to function, 653# especially when transferring >1 byte. It seems to be much more stable 654# if STCNT is set to one before the transfer, and SDONE (in SSTAT0) is 655# polled for transfer completion - for both output _and_ input. The 656# only theory I have is that SPIORDY doesn't drop right away when SCSIDATL 657# is accessed (like the documentation says it does), and that on a longer 658# cable run, the sequencer code was fast enough to loop back and see 659# an SPIORDY that hadn't dropped yet. 660# 661p_mesgout3: 662 mvi STCNT+0, 0x01 663 mov SCSIDATL,SINDIR 664 665p_mesgout4: 666 test SSTAT0,0x4 jz p_mesgout4 # SDONE 667 dec DINDEX 668 test DINDEX,0xff jnz p_mesgout2 669 670# If the next bus phase after ATN drops is a message out, it means 671# that the target is requesting that the last message(s) be resent. 672# 673p_mesgout5: 674 test SSTAT1,0x8 jnz p_mesgout6 # BUSFREE 675 test SSTAT1,0x1 jz p_mesgout5 # REQINIT 676 677 and A,0xe0,SCSISIGI # CDI|IOI|MSGI 678 cmp A,0xa0 jne p_mesgout6 679 mvi 0x10 call scsisig # ATNO - re-assert ATN 680 681 jmp ITloop 682 683p_mesgout6: 684 mvi CLRSINT1,0x40 # CLRATNO - in case of PHASEMIS 685 and FLAGS,0xdf # no active msg 686 jmp ITloop 687 688# Message in phase. Bytes are read using Automatic PIO mode, but not 689# using inb. This alleviates a race condition, namely that if ATN had 690# to be asserted under Automatic PIO mode, it had to beat the SCSI 691# circuitry sending an ACK to the target. This showed up under heavy 692# loads and really confused things, since ABORT commands wouldn't be 693# seen by the drive after an IDENTIFY message in until it had changed 694# to a data I/O phase. 695# 696p_mesgin: 697 mvi 0xe0 call scsisig # CDO|IOO|MSGO 698 mvi A call inb_first # read the 1st message byte 699 mvi REJBYTE,A # save it for the driver 700 701 cmp ALLZEROS,A jne p_mesgin1 702 703# We got a "command complete" message, so put the SCB pointer 704# into the Queue Out, and trigger a completion interrupt. 705# Check status for non zero return and interrupt driver if needed 706# This allows the driver to interpret errors only when they occur 707# instead of always uploading the scb. If the status is SCSI_CHECK, 708# the driver will download a new scb requesting sense to replace 709# the old one, modify the "waiting for selection" SCB list and set 710# RETURN_1 to 0x80. If RETURN_1 is set to 0x80 the sequencer imediately 711# jumps to main loop where it will run down the waiting SCB list. 712# If the kernel driver does not wish to request sense, it need 713# only clear RETURN_1, and the command is allowed to complete. We don't 714# bother to post to the QOUTFIFO in the error case since it would require 715# extra work in the kernel driver to ensure that the entry was removed 716# before the command complete code tried processing it. 717 718# First check for residuals 719 test SCBARRAY+18,0xff jnz resid 720 721check_status: 722 test SCBARRAY+14,0xff jz status_ok # 0 Status? 723 mvi INTSTAT,BAD_STATUS # let driver know 724 test RETURN_1, 0x80 jz status_ok 725 jmp p_mesgin_done 726 727status_ok: 728# First, mark this target as free. 729 test SCBARRAY+0,TAG_ENB jnz complete # Tagged command 730 and FUNCTION1,0x70,SCBARRAY+1 731 mov A,FUNCTION1 732 test SCBARRAY+1,0x88 jz clear_a 733 xor ACTIVE_B,A 734 jmp complete 735 736clear_a: 737 xor ACTIVE_A,A 738 739 test SCBARRAY+11,0xff jnz complete # Immediate message complete 740# Pause the sequencer until the driver gets around to handling the command 741# complete. This is so that any action that might require carefull timing 742# with the completion of this command can occur. 743 mvi INTSTAT,IMMEDDONE 744 jmp poll_for_work 745complete: 746 mov QOUTFIFO,SCBPTR 747 mvi INTSTAT,CMDCMPLT 748 jmp p_mesgin_done 749 750# If we have a residual count, interrupt and tell the host. Other 751# alternatives are to pause the sequencer on all command completes (yuck), 752# dma the resid directly to the host (slick, but a ton of instructions), or 753# have the sequencer pause itself when it encounters a non-zero resid 754# (unecessary pause just to flag the command -- yuck, but takes few instructions 755# and since it shouldn't happen that often is good enough for our purposes). 756 757resid: 758 mvi INTSTAT,RESIDUAL 759 jmp check_status 760 761# Is it an extended message? We only support the synchronous and wide data 762# transfer request messages, which will probably be in response to 763# WDTR or SDTR message outs from us. If it's not SDTR or WDTR, reject it - 764# apparently this can be done after any message in byte, according 765# to the SCSI-2 spec. 766# 767p_mesgin1: 768 cmp A,1 jne p_mesgin2 # extended message code? 769 770 mvi ARG_1 call inb_next # extended message length 771 mvi A call inb_next # extended message code 772 773 cmp A,1 je p_mesginSDTR # Syncronous negotiation message 774 cmp A,3 je p_mesginWDTR # Wide negotiation message 775 jmp p_mesginN 776 777p_mesginWDTR: 778 cmp ARG_1,2 jne p_mesginN # extended mesg length = 2 779 mvi A call inb_next # Width of bus 780 mvi INTSTAT,MSG_WDTR # let driver know 781 test RETURN_1,0x80 jz p_mesgin_done# Do we need to send WDTR? 782 783# We didn't initiate the wide negotiation, so we must respond to the request 784 and RETURN_1,0x7f # Clear the SEND_WDTR Flag 785 or FLAGS,ACTIVE_MSG 786 mvi DINDEX,MSG_START+0 787 mvi MSG_START+0 call mk_wdtr # build WDTR message 788 or SINDEX,0x10,SIGSTATE # turn on ATNO 789 call scsisig 790 jmp p_mesgin_done 791 792p_mesginSDTR: 793 cmp ARG_1,3 jne p_mesginN # extended mesg length = 3 794 mvi ARG_1 call inb_next # xfer period 795 mvi A call inb_next # REQ/ACK offset 796 mvi INTSTAT,MSG_SDTR # call driver to convert 797 798 test RETURN_1,0xc0 jz p_mesgin_done# Do we need to mk_sdtr or rej? 799 test RETURN_1,0x40 jnz p_mesginN # Requested SDTR too small - rej 800 or FLAGS,ACTIVE_MSG 801 mvi DINDEX, MSG_START+0 802 mvi MSG_START+0 call mk_sdtr 803 or SINDEX,0x10,SIGSTATE # turn on ATNO 804 call scsisig 805 jmp p_mesgin_done 806 807# Is it a disconnect message? Set a flag in the SCB to remind us 808# and await the bus going free. 809# 810p_mesgin2: 811 cmp A,4 jne p_mesgin3 # disconnect code? 812 813 or SCBARRAY+0,DISCONNECTED 814 jmp p_mesgin_done 815 816# Save data pointers message? Copy working values into the SCB, 817# usually in preparation for a disconnect. 818# 819p_mesgin3: 820 cmp A,2 jne p_mesgin4 # save data pointers code? 821 822 call sg_ram2scb 823 jmp p_mesgin_done 824 825# Restore pointers message? Data pointers are recopied from the 826# SCB anytime we enter a data phase for the first time, so all 827# we need to do is clear the DPHASE flag and let the data phase 828# code do the rest. 829# 830p_mesgin4: 831 cmp A,3 jne p_mesgin5 # restore pointers code? 832 833 and FLAGS,0xfb # !DPHASE we'll reload them 834 # the next time through 835 jmp p_mesgin_done 836 837# Identify message? For a reconnecting target, this tells us the lun 838# that the reconnection is for - find the correct SCB and switch to it, 839# clearing the "disconnected" bit so we don't "find" it by accident later. 840# 841p_mesgin5: 842 test A,0x80 jz p_mesgin6 # identify message? 843 844 test A,0x78 jnz p_mesginN # !DiscPriv|!LUNTAR|!Reserved 845 846 and A,0x07 # lun in lower three bits 847 or SAVED_TCL,A,SELID 848 and SAVED_TCL,0xf7 849 and A,0x08,SBLKCTL # B Channel?? 850 or SAVED_TCL,A 851 call inb_last # ACK 852 mov ALLZEROS call findSCB 853setup_SCB: 854 and SCBARRAY+0,0xfb # clear disconnect bit in SCB 855 or FLAGS,IDENTIFY_SEEN # make note of IDENTIFY 856 857 jmp ITloop 858get_tag: 859 mvi A call inb_first 860 cmp A,0x20 jne return # Simple Tag message? 861 mvi A call inb_next 862 call inb_last 863 test A,0xf0 jnz abort_tag # Tag in range? 864 mov SCBPTR,A 865 mov A,SAVED_TCL 866 cmp SCBARRAY+1,A jne abort_tag 867 test SCBARRAY+0,TAG_ENB jz abort_tag 868 ret 869abort_tag: 870 or SINDEX,0x10,SIGSTATE # turn on ATNO 871 call scsisig 872 mvi INTSTAT,ABORT_TAG # let driver know 873 mvi 0xd call mk_mesg # ABORT TAG message 874 ret 875 876# Message reject? Let the kernel driver handle this. If we have an 877# outstanding WDTR or SDTR negotiation, assume that it's a response from 878# the target selecting 8bit or asynchronous transfer, otherwise just ignore 879# it since we have no clue what it pertains to. 880# 881p_mesgin6: 882 cmp A,7 jne p_mesgin7 # message reject code? 883 884 mvi INTSTAT, MSG_REJECT 885 jmp p_mesgin_done 886 887# [ ADD MORE MESSAGE HANDLING HERE ] 888# 889p_mesgin7: 890 891# We have no idea what this message in is, and there's no way 892# to pass it up to the kernel, so we issue a message reject and 893# hope for the best. Since we're now using manual PIO mode to 894# read in the message, there should no longer be a race condition 895# present when we assert ATN. In any case, rejection should be a 896# rare occurrence - signal the driver when it happens. 897# 898p_mesginN: 899 or SINDEX,0x10,SIGSTATE # turn on ATNO 900 call scsisig 901 mvi INTSTAT,SEND_REJECT # let driver know 902 903 mvi 0x7 call mk_mesg # MESSAGE REJECT message 904 905p_mesgin_done: 906 call inb_last # ack & turn auto PIO back on 907 jmp ITloop 908 909 910# Bus free phase. It might be useful to interrupt the device 911# driver if we aren't expecting this. For now, make sure that 912# ATN isn't being asserted and look for a new command. 913# 914p_busfree: 915 mvi CLRSINT1,0x40 # CLRATNO 916 clr SIGSTATE 917 918# if this is an immediate command, perform a psuedo command complete to 919# notify the driver. 920 test SCBARRAY+11,0xff jz status_ok 921 jmp poll_for_work 922 923# Instead of a generic bcopy routine that requires an argument, we unroll 924# the cases that are actually used, and call them explicitly. This 925# not only reduces the overhead of doing a bcopy, but ends up saving space 926# in the program since you don't have to put the argument into the accumulator 927# before the call. Both functions expect DINDEX to contain the destination 928# address and SINDEX to contain the source address. 929bcopy_7: 930 mov DINDIR,SINDIR 931 mov DINDIR,SINDIR 932bcopy_5: 933 mov DINDIR,SINDIR 934bcopy_4: 935 mov DINDIR,SINDIR 936bcopy_3: 937 mov DINDIR,SINDIR 938 mov DINDIR,SINDIR 939 mov DINDIR,SINDIR ret 940 941bcopy_7_dfdat: 942 mov DINDIR,DFDAT 943 mov DINDIR,DFDAT 944bcopy_5_dfdat: 945 mov DINDIR,DFDAT 946bcopy_4_dfdat: 947 mov DINDIR,DFDAT 948bcopy_3_dfdat: 949 mov DINDIR,DFDAT 950 mov DINDIR,DFDAT 951 mov DINDIR,DFDAT ret 952 953# Locking the driver out, build a one-byte message passed in SINDEX 954# if there is no active message already. SINDEX is returned intact. 955# 956mk_mesg: 957 mvi SEQCTL,0x50 # PAUSEDIS|FASTMODE 958 test FLAGS,ACTIVE_MSG jnz mk_mesg1 # active message? 959 960 or FLAGS,ACTIVE_MSG # if not, there is now 961 mvi MSG_LEN,1 # length = 1 962 mov MSG_START+0,SINDEX # 1-byte message 963 964mk_mesg1: 965 mvi SEQCTL,0x10 ret # !PAUSEDIS|FASTMODE 966 967# Carefully read data in Automatic PIO mode. I first tried this using 968# Manual PIO mode, but it gave me continual underrun errors, probably 969# indicating that I did something wrong, but I feel more secure leaving 970# Automatic PIO on all the time. 971# 972# According to Adaptec's documentation, an ACK is not sent on input from 973# the target until SCSIDATL is read from. So we wait until SCSIDATL is 974# latched (the usual way), then read the data byte directly off the bus 975# using SCSIBUSL. When we have pulled the ATN line, or we just want to 976# acknowledge the byte, then we do a dummy read from SCISDATL. The SCSI 977# spec guarantees that the target will hold the data byte on the bus until 978# we send our ACK. 979# 980# The assumption here is that these are called in a particular sequence, 981# and that REQ is already set when inb_first is called. inb_{first,next} 982# use the same calling convention as inb. 983# 984inb_first: 985 clr STCNT+2 986 clr STCNT+1 987 mov DINDEX,SINDEX 988 mov DINDIR,SCSIBUSL ret # read byte directly from bus 989 990inb_next: 991 mov DINDEX,SINDEX # save SINDEX 992 993 mvi STCNT+0,1 # xfer one byte 994 mov NONE,SCSIDATL # dummy read from latch to ACK 995inb_next1: 996 test SSTAT0,0x4 jz inb_next1 # SDONE 997inb_next2: 998 test SSTAT0,0x2 jz inb_next2 # SPIORDY - wait for next byte 999 mov DINDIR,SCSIBUSL ret # read byte directly from bus 1000 1001inb_last: 1002 mvi STCNT+0,1 # ACK with dummy read 1003 mov NONE,SCSIDATL 1004inb_last1: 1005 test SSTAT0,0x4 jz inb_last1 # wait for completion 1006 ret 1007 1008# DMA data transfer. HADDR and HCNT must be loaded first, and 1009# SINDEX should contain the value to load DFCNTRL with - 0x3d for 1010# host->scsi, or 0x39 for scsi->host. The SCSI channel is cleared 1011# during initialization. 1012# 1013dma: 1014 mov DFCNTRL,SINDEX 1015dma1: 1016 test SSTAT0,0x1 jnz dma3 # DMADONE 1017 test SSTAT1,0x10 jz dma1 # PHASEMIS, ie. underrun 1018 1019# We will be "done" DMAing when the transfer count goes to zero, or 1020# the target changes the phase (in light of this, it makes sense that 1021# the DMA circuitry doesn't ACK when PHASEMIS is active). If we are 1022# doing a SCSI->Host transfer, the data FIFO should be flushed auto- 1023# magically on STCNT=0 or a phase change, so just wait for FIFO empty 1024# status. 1025# 1026dma3: 1027 test SINDEX,0x4 jnz dma5 # DIRECTION 1028dma4: 1029 test DFSTATUS,0x1 jz dma4 # !FIFOEMP 1030 1031# Now shut the DMA enables off and make sure that the DMA enables are 1032# actually off first lest we get an ILLSADDR. 1033# 1034dma5: 1035 clr DFCNTRL # disable DMA 1036dma6: 1037 test DFCNTRL,0x38 jnz dma6 # SCSIENACK|SDMAENACK|HDMAENACK 1038 1039 ret 1040 1041dma_finish: 1042 test DFSTATUS,0x8 jz dma_finish # HDONE 1043 1044 clr DFCNTRL # disable DMA 1045dma_finish2: 1046 test DFCNTRL,0x8 jnz dma_finish2 # HDMAENACK 1047 ret 1048 1049# Common SCSI initialization for selection and reselection. Expects 1050# the target SCSI ID to be in the upper four bits of SINDEX, and A's 1051# contents are stomped on return. 1052# 1053initialize_scsiid: 1054 and SINDEX,0xf0 # Get target ID 1055 and A,0x0f,SCSIID 1056 or SINDEX,A 1057 mov SCSIID,SINDEX ret 1058 1059initialize_for_target: 1060# Turn on Automatic PIO mode now, before we expect to see a REQ 1061# from the target. It shouldn't hurt anything to leave it on. Set 1062# CLRCHN here before the target has entered a data transfer mode - 1063# with synchronous SCSI, if you do it later, you blow away some 1064# data in the SCSI FIFO that the target has already sent to you. 1065# 1066 clr SIGSTATE 1067 1068 mvi SXFRCTL0,0x8a # DFON|SPIOEN|CLRCHN 1069 1070# Make sure that the system knows we have not been through a DATA 1071# phase. 1072 and FLAGS, 0xfb # !DPHASE 1073 1074# Initialize SCSIRATE with the appropriate value for this target. 1075# 1076 call ndx_dtr 1077 mov SCSIRATE,SINDIR ret 1078 1079# Assert that if we've been reselected, then we've seen an IDENTIFY 1080# message. 1081# 1082assert: 1083 test FLAGS,RESELECTED jz return # reselected? 1084 test FLAGS,IDENTIFY_SEEN jnz return # seen IDENTIFY? 1085 1086 mvi INTSTAT,NO_IDENT ret # no - cause a kernel panic 1087 1088# Locate the SCB matching the target ID/channel/lun in SAVED_TCL and switch 1089# the SCB to it. Have the kernel print a warning message if it can't be 1090# found, and generate an ABORT message to the target. SINDEX should be 1091# cleared on call. 1092# 1093findSCB: 1094 mov A,SAVED_TCL 1095 mov SCBPTR,SINDEX # switch to new SCB 1096 cmp SCBARRAY+1,A jne findSCB1 # target ID/channel/lun match? 1097 test SCBARRAY+0,DISCONNECTED jz findSCB1 # should be disconnected 1098 test SCBARRAY+0,TAG_ENB jnz get_tag 1099 ret 1100 1101findSCB1: 1102 inc SINDEX 1103 mov A,SCBCOUNT 1104 cmp SINDEX,A jne findSCB 1105 1106 mvi INTSTAT,NO_MATCH # not found - signal kernel 1107 mvi 0x6 call mk_mesg # ABORT message 1108 1109 or SINDEX,0x10,SIGSTATE # assert ATNO 1110 call scsisig 1111 ret 1112 1113# Make a working copy of the scatter-gather parameters from the SCB. 1114# 1115sg_scb2ram: 1116 mvi DINDEX,HADDR 1117 mvi SCBARRAY+19 call bcopy_7 1118 1119 mvi DINDEX,STCNT 1120 mvi SCBARRAY+23 call bcopy_3 1121 1122 mov SG_COUNT,SCBARRAY+2 1123 1124 mvi DINDEX,SG_NEXT 1125 mvi SCBARRAY+3 call bcopy_4 1126 ret 1127 1128# Copying RAM values back to SCB, for Save Data Pointers message, but 1129# only if we've actually been into a data phase to change them. This 1130# protects against bogus data in scratch ram and the residual counts 1131# since they are only initialized when we go into data_in or data_out. 1132# 1133sg_ram2scb: 1134 test FLAGS, DPHASE jz return 1135 mov SCBARRAY+2,SG_COUNT 1136 1137 mvi DINDEX,SCBARRAY+3 1138 mvi SG_NEXT call bcopy_4 1139 1140 mvi DINDEX,SCBARRAY+19 1141 mvi SHADDR call bcopy_4 1142 1143# Use the residual number since STCNT is corrupted by any message transfer 1144 mvi SCBARRAY+15 call bcopy_3 1145 ret 1146 1147# Add the array base SYNCNEG to the target offset (the target address 1148# is in SCSIID), and return the result in SINDEX. The accumulator 1149# contains the 3->8 decoding of the target ID on return. 1150# 1151ndx_dtr: 1152 shr A,SCSIID,4 1153 test SBLKCTL,0x08 jz ndx_dtr_2 1154 or A,0x08 # Channel B entries add 8 1155ndx_dtr_2: 1156 add SINDEX,SYNCNEG,A 1157 1158 and FUNCTION1,0x70,SCSIID # 3-bit target address decode 1159 mov A,FUNCTION1 ret 1160 1161# If we need to negotiate transfer parameters, build the WDTR or SDTR message 1162# starting at the address passed in SINDEX. DINDEX is modified on return. 1163# The SCSI-II spec requires that Wide negotiation occur first and you can 1164# only negotiat one or the other at a time otherwise in the event of a message 1165# reject, you wouldn't be able to tell which message was the culpret. 1166# 1167mk_dtr: 1168 test SCBARRAY+0,0x90 jz return # NEEDWDTR|NEEDSDTR 1169 test SCBARRAY+0,NEEDWDTR jnz mk_wdtr_16bit 1170 or FLAGS, MAX_OFFSET # Force an offset of 15 or 8 if WIDE 1171 1172mk_sdtr: 1173 mvi DINDIR,1 # extended message 1174 mvi DINDIR,3 # extended message length = 3 1175 mvi DINDIR,1 # SDTR code 1176 call sdtr_to_rate 1177 mov DINDIR,RETURN_1 # REQ/ACK transfer period 1178 test FLAGS, MAX_OFFSET jnz mk_sdtr_max_offset 1179 and DINDIR,0x0f,SINDIR # Sync Offset 1180 1181mk_sdtr_done: 1182 add MSG_LEN,-MSG_START+0,DINDEX ret # update message length 1183 1184mk_sdtr_max_offset: 1185# We're initiating sync negotiation, so request the max offset we can (15 or 8) 1186 xor FLAGS, MAX_OFFSET 1187 test SCSIRATE, 0x80 jnz wmax_offset # Talking to a WIDE device? 1188 mvi DINDIR, MAX_OFFSET_8BIT 1189 jmp mk_sdtr_done 1190 1191wmax_offset: 1192 mvi DINDIR, MAX_OFFSET_WIDE 1193 jmp mk_sdtr_done 1194 1195mk_wdtr_16bit: 1196 mvi ARG_1,BUS_16_BIT 1197mk_wdtr: 1198 mvi DINDIR,1 # extended message 1199 mvi DINDIR,2 # extended message length = 2 1200 mvi DINDIR,3 # WDTR code 1201 mov DINDIR,ARG_1 # bus width 1202 1203 add MSG_LEN,-MSG_START+0,DINDEX ret # update message length 1204 1205# Set SCSI bus control signal state. This also saves the last-written 1206# value into a location where the higher-level driver can read it - if 1207# it has to send an ABORT or RESET message, then it needs to know this 1208# so it can assert ATN without upsetting SCSISIGO. The new value is 1209# expected in SINDEX. Change the actual state last to avoid contention 1210# from the driver. 1211# 1212scsisig: 1213 mov SIGSTATE,SINDEX 1214 mov SCSISIGO,SINDEX ret 1215 1216sdtr_to_rate: 1217 call ndx_dtr # index scratch space for target 1218 shr A,SINDIR,0x4 1219 dec SINDEX #Preserve SINDEX 1220 and A,0x7 1221 clr RETURN_1 1222sdtr_to_rate_loop: 1223 test A,0x0f jz sdtr_to_rate_done 1224 add RETURN_1,0x18 1225 dec A 1226 jmp sdtr_to_rate_loop 1227sdtr_to_rate_done: 1228 shr RETURN_1,0x2 1229 add RETURN_1,0x18 ret 1230 1231return: 1232 ret 1233