aic7xxx.seq revision 21982
1130268Sdwmalone/*+M*********************************************************************** 278064Sume *Adaptec 274x/284x/294x device driver for Linux and FreeBSD. 355163Sshin * 455163Sshin *Copyright (c) 1994 John Aycock 555163Sshin * The University of Calgary Department of Computer Science. 655163Sshin * All rights reserved. 755163Sshin * 855163Sshin *FreeBSD, Twin, Wide, 2 command per target support, tagged queuing, 955163Sshin *SCB paging and other optimizations: 1055163Sshin *Copyright (c) 1994, 1995, 1996 Justin Gibbs. All rights reserved. 1155163Sshin * 1255163Sshin *Redistribution and use in source and binary forms, with or without 1355163Sshin *modification, are permitted provided that the following conditions 1455163Sshin *are met: 1555163Sshin *1. Redistributions of source code must retain the above copyright 1655163Sshin * notice, this list of conditions, and the following disclaimer. 1755163Sshin *2. Redistributions in binary form must reproduce the above copyright 1855163Sshin * notice, this list of conditions and the following disclaimer in the 1955163Sshin * documentation and/or other materials provided with the distribution. 2055163Sshin *3. All advertising materials mentioning features or use of this software 2155163Sshin * must display the following acknowledgement: 2255163Sshin * This product includes software developed by the University of Calgary 2355163Sshin * Department of Computer Science and its contributors. 2455163Sshin *4. Neither the name of the University nor the names of its contributors 2555163Sshin * may be used to endorse or promote products derived from this software 2655163Sshin * without specific prior written permission. 2755163Sshin * 2855163Sshin *THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 2955163Sshin *ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30141580Sru *IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 3155163Sshin *ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 32196475Sume *FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 3355163Sshin *DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 3459849Sphantom *OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 3555163Sshin *HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 3655163Sshin *LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 3755163Sshin *OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38130268Sdwmalone *SUCH DAMAGE. 3955163Sshin * 4055163Sshin *-M************************************************************************/ 4168965Sru 4262637SkrisVERSION AIC7XXX_SEQ_VER "$FreeBSD: head/sys/dev/aic7xxx/aic7xxx.seq 21982 1997-01-24 21:57:47Z gibbs $" 43196475Sume 4462637Skris#if defined(__NetBSD__) 4562637Skris#include "../../../../dev/ic/aic7xxxreg.h" 4662637Skris#include "../../../../scsi/scsi_message.h" 4762637Skris#elif defined(__FreeBSD__) 4862637Skris#include "../../dev/aic7xxx/aic7xxx_reg.h" 4962637Skris#include "../../scsi/scsi_message.h" 5062637Skris#endif 5162637Skris 5255163Sshin/* 5362637Skris * We can't just use ACCUM in the sequencer code because it 5462637Skris * must be treated specially by the assembler, and it currently 5555163Sshin * looks for the symbol 'A'. This is the only register defined in 5662637Skris * the assembler's symbol space. 5762637Skris */ 5855163SshinA = ACCUM 5962637Skris 6062637Skris/* 6155163Sshin * A few words on the waiting SCB list: 6262637Skris * After starting the selection hardware, we check for reconnecting targets 6362637Skris * as well as for our selection to complete just in case the reselection wins 6455163Sshin * bus arbitration. The problem with this is that we must keep track of the 6562637Skris * SCB that we've already pulled from the QINFIFO and started the selection 6662637Skris * on just in case the reselection wins so that we can retry the selection at 67196475Sume * a later time. This problem cannot be resolved by holding a single entry 68196475Sume * in scratch ram since a reconnecting target can request sense and this will 69196475Sume * create yet another SCB waiting for selection. The solution used here is to 7062637Skris * use byte 27 of the SCB as a psuedo-next pointer and to thread a list 7162637Skris * of SCBs that are awaiting selection. Since 0-0xfe are valid SCB indexes, 7262637Skris * SCB_LIST_NULL is 0xff which is out of range. An entry is also added to 7355163Sshin * this list everytime a request sense occurs or after completing a non-tagged 7455163Sshin * command for which a second SCB has been queued. The sequencer will 75131754Sru * automatically consume the entries. 76130268Sdwmalone */ 77131754Sru 78130268Sdwmalone/* 79130268Sdwmalone * We assume that the kernel driver may reset us at any time, even in the 80130268Sdwmalone * middle of a DMA, so clear DFCNTRL too. 81130268Sdwmalone */ 82130268Sdwmalonereset: 83130268Sdwmalone clr DFCNTRL 84131754Sru clr SCSISIGO /* De-assert BSY */ 85131754Sru 86131754Srup_busfree: 87130268Sdwmalone or SXFRCTL0, CLRCHN 88130268Sdwmalone clr SCSIRATE /* 8955163Sshin * We don't know the target we will 90196475Sume * connect to, so default to narrow 91196475Sume * transfers to avoid parity problems. 92196475Sume */ 93196475Sume mvi SCSISEQ,ENRSELI /* Always allow reselection */ 9455163Sshin mvi LASTPHASE, P_BUSFREE 9555163Sshin and FLAGS,0x07 /* clear target specific flags */ 9662637Skrispoll_for_work: 9762637Skris /* 9862637Skris * Are we a twin channel device? 9962637Skris * For fairness, we check the other bus first, 100130135Sru * since we just finished a transaction on the 101130135Sru * current channel. 102122574Sume */ 103122574Sume test FLAGS,TWIN_BUS jz start2 10455163Sshin xor SBLKCTL,SELBUSB /* Toggle to the other bus */ 10555163Sshin test SSTAT0,SELDI jnz reselect 10655163Sshin xor SBLKCTL,SELBUSB /* Toggle to the original bus */ 10755163Sshinstart2: 10855163Sshin test SSTAT0,SELDI jnz reselect 10955163Sshin cmp WAITING_SCBH,SCB_LIST_NULL je test_queue 11055163Sshinstart_waiting: 11155163Sshin /* 11255163Sshin * Pull the first entry off of the waiting SCB list 113154190Spav * We don't have to "test_busy" because only transactions that 114154190Spav * have passed that test can be in the WAITING_SCB list. 115154190Spav */ 11655163Sshin mov SCBPTR,WAITING_SCBH 11755163Sshin jmp start_scb2 118176154Sdwmalonetest_queue: 119176154Sdwmalone /* Has the driver posted any work for us? */ 120176154Sdwmalone mov A, QCNTMASK 12155163Sshin test QINCNT,A jz poll_for_work 12255163Sshin 12355163Sshin/* 12455163Sshin * We have at least one queued SCB now and we don't have any 12555163Sshin * SCBs in the list of SCBs awaiting selection. If we have 12655163Sshin * any SCBs availible for use, pull the tag from the QINFIFO 12755163Sshin * and get to work on it. 128153638Sdd */ 129153638Sdd test FLAGS, PAGESCBS jz dequeue_scb 130153638Sdd mov ALLZEROS call get_free_or_disc_scb 131153638Sdd cmp SINDEX, SCB_LIST_NULL je poll_for_work 132153638Sdddequeue_scb: 133153638Sdd mov CUR_SCBID,QINFIFO 134153638Sdd test FLAGS, PAGESCBS jnz dma_queued_scb 135153638Sdd /* In the non-paging case, the SCBID == hardware SCB index */ 136153638Sdd mov SCBPTR, CUR_SCBID 137153638Sdddma_queued_scb: 13855163Sshin/* 13955163Sshin * DMA the SCB from host ram into the current SCB location. 14055163Sshin */ 141176154Sdwmalone mvi DMAPARAMS, 0xd /* HDMAEN|DIRECTION|FIFORESET */ 142176154Sdwmalone mov CUR_SCBID call dma_scb 143176154Sdwmalone 14455163Sshin/* 14555163Sshin * See if there is not already an active SCB for this target. This code 14655163Sshin * locks out on a per target basis instead of target/lun. Although this 14755163Sshin * is not ideal for devices that have multiple luns active at the same 14855163Sshin * time, it is faster than looping through all SCB's looking for active 149130268Sdwmalone * commands. We also don't have enough spare SCB space for us to store the 150131754Sru * SCBID of the currently busy transaction for each target/lun making it 151130268Sdwmalone * impossible to link up the SCBs. 152130268Sdwmalone */ 153130268Sdwmalonetest_busy: 154130268Sdwmalone test SCB_CONTROL, TAG_ENB jnz start_scb 155131754Sru mov SAVED_SCBPTR, SCBPTR 156130268Sdwmalone mov SCB_TCL call index_untagged_scb 157131754Sru mvi SEQCTL,0x50 /* PAUSEDIS|FASTMODE */ 158130268Sdwmalone mov ARG_1, SINDIR /* 159131754Sru * ARG_1 should 160130268Sdwmalone * now have the SCB ID of 161131754Sru * any active, non-tagged, 162130268Sdwmalone * command for this target. 163131754Sru */ 164130268Sdwmalone cmp ARG_1, SCB_LIST_NULL je make_busy 165130268Sdwmalone test FLAGS, PAGESCBS jz simple_busy_link 166130268Sdwmalone /* 167130268Sdwmalone * Put this SCB back onto the free list. It 168130268Sdwmalone * may be necessary to satisfy the search for 169130268Sdwmalone * the active SCB. 170130268Sdwmalone */ 17155163Sshin mov SCBPTR, SAVED_SCBPTR 172186845Sdanger call add_scb_to_free_list 17359849Sphantom /* Find the active SCB */ 17459849Sphantom mov ALLZEROS call findSCB 175130135Sru /* 17655163Sshin * If we couldn't find it, tell the kernel. This should 17755163Sshin * never happen. 17855163Sshin */ 17955163Sshin cmp SINDEX, SCB_LIST_NULL jne paged_busy_link 18055163Sshin mvi INTSTAT, NO_MATCH_BUSY 18155163Sshinpaged_busy_link: 18255163Sshin /* Link us in */ 18355163Sshin mov SCB_LINKED_NEXT, CUR_SCBID 18455163Sshin /* Put it back on the disconnected list */ 185130135Sru call add_scb_to_disc_list 186 mvi SEQCTL,0x10 /* FASTMODE */ 187 jmp poll_for_work 188simple_busy_link: 189 mov SCBPTR, ARG_1 190 mov SCB_LINKED_NEXT, CUR_SCBID 191 mvi SEQCTL,0x10 /* FASTMODE */ 192 jmp poll_for_work 193make_busy: 194 mvi SEQCTL,0x10 /* FASTMODE */ 195 mov DINDIR, CUR_SCBID 196 mov SCBPTR, SAVED_SCBPTR 197 198start_scb: 199 /* 200 * Place us on the waiting list in case our selection 201 * doesn't win during bus arbitration. 202 */ 203 mov SCB_NEXT,WAITING_SCBH 204 mov WAITING_SCBH, SCBPTR 205start_scb2: 206 and SINDEX,0xf7,SBLKCTL /* Clear the channel select bit */ 207 and A,0x08,SCB_TCL /* Get new channel bit */ 208 or SINDEX,A 209 mov SBLKCTL,SINDEX /* select channel */ 210 mov SCB_TCL call initialize_scsiid 211 212/* 213 * Enable selection phase as an initiator, and do automatic ATN 214 * after the selection. We do this now so that we can overlap the 215 * rest of our work to set up this target with the arbitration and 216 * selection bus phases. 217 */ 218start_selection: 219 mvi SCSISEQ,0x58 /* ENSELO|ENAUTOATNO|ENRSELI */ 220 221/* 222 * As soon as we get a successful selection, the target should go 223 * into the message out phase since we have ATN asserted. Prepare 224 * the message to send. 225 * 226 * Messages are stored in scratch RAM starting with a length byte 227 * followed by the message itself. 228 */ 229 230mk_identify: 231 and MSG0,0x7,SCB_TCL /* lun */ 232 and A,DISCENB,SCB_CONTROL /* mask off disconnect privledge */ 233 or MSG0,A /* or in disconnect privledge */ 234 or MSG0,MSG_IDENTIFYFLAG 235 mvi MSG_LEN, 1 236 237/* 238 * Send a tag message if TAG_ENB is set in the SCB control block. 239 * Use SCB_TAG (the position in the kernel's SCB array) as the tag value. 240 */ 241mk_tag: 242 test SCB_CONTROL,TAG_ENB jz mk_message 243 and MSG1,0x23,SCB_CONTROL 244 mov MSG2,SCB_TAG 245 add MSG_LEN,2 /* update message length */ 246 247/* 248 * Interrupt the driver, and allow it to tweak the message buffer 249 * if it asks. 250 */ 251mk_message: 252 test SCB_CONTROL,MK_MESSAGE jz wait_for_selection 253 254 mvi INTSTAT,AWAITING_MSG 255 256wait_for_selection: 257 test SSTAT0,SELDO jnz select 258 test SSTAT0,SELDI jz wait_for_selection 259 260/* 261 * Reselection has been initiated by a target. Make a note that we've been 262 * reselected, but haven't seen an IDENTIFY message from the target yet. 263 */ 264reselect: 265 clr MSG_LEN /* Don't have anything in the mesg buffer */ 266 /* XXX test for and handle ONE BIT condition */ 267 and SAVED_TCL, 0xf0, SELID 268 or FLAGS,RESELECTED 269 jmp select2 270 271/* 272 * After the selection, remove this SCB from the "waiting SCB" 273 * list. This is achieved by simply moving our "next" pointer into 274 * WAITING_SCBH. Our next pointer will be set to null the next time this 275 * SCB is used, so don't bother with it now. 276 */ 277select: 278 mov WAITING_SCBH,SCB_NEXT 279select2: 280 /* Turn off the selection hardware */ 281 mvi SCSISEQ,ENAUTOATNP /* 282 * ATN on parity errors 283 * for "in" phases 284 */ 285 mvi CLRSINT0,0x60 /* CLRSELDI|CLRSELDO */ 286 mvi CLRSINT1,CLRBUSFREE 287 or SIMODE1, ENBUSFREE /* 288 * We aren't expecting a 289 * bus free, so interrupt 290 * the kernel driver if it 291 * happens. 292 */ 293/* 294 * Initialize SCSIRATE with the appropriate value for this target. 295 * The SCSIRATE settings for each target are stored in an array 296 * based at TARG_SCRATCH. 297 */ 298ndx_dtr: 299 shr A,SAVED_TCL,4 300 test SBLKCTL,SELBUSB jz ndx_dtr_2 301 or SAVED_TCL, SELBUSB /* Add the channel bit while we're here */ 302 or A,0x08 /* Channel B entries add 8 */ 303ndx_dtr_2: 304 add SINDEX,TARG_SCRATCH,A 305 mov SCSIRATE,SINDIR 306 307/* 308 * Initialize Ultra mode setting and clear the SCSI channel. 309 */ 310ultra: 311 and DINDEX,0xdf,SXFRCTL0 /* default to Ultra disabled */ 312 mvi SINDEX, ULTRA_ENB_B 313 test SAVED_TCL, 0x80 jnz ultra_2 /* Target ID > 7 */ 314 test SBLKCTL, SELBUSB jnz ultra_2 /* Second channel device */ 315 dec SINDEX 316ultra_2: 317 mov FUNCTION1,SAVED_TCL 318 mov A,FUNCTION1 319 test SINDIR, A jz set_sxfrctl0 320 or DINDEX, ULTRAEN 321 322set_sxfrctl0: 323 mov SXFRCTL0,DINDEX 324 325/* 326 * Main loop for information transfer phases. If BSY is false, then 327 * we have a bus free condition, expected or not. Otherwise, wait 328 * for the target to assert REQ before checking MSG, C/D and I/O 329 * for the bus phase. 330 * 331 */ 332ITloop: 333 test SSTAT1,BUSFREE jnz p_busfree 334 test SSTAT1,REQINIT jz ITloop 335 336 and A,PHASE_MASK,SCSISIGI 337 mov LASTPHASE,A 338 mov SCSISIGO,A 339 340 cmp ALLZEROS,A je p_dataout 341 cmp A,P_DATAIN je p_datain 342 cmp A,P_COMMAND je p_command 343 cmp A,P_MESGOUT je p_mesgout 344 cmp A,P_STATUS je p_status 345 cmp A,P_MESGIN je p_mesgin 346 347 mvi INTSTAT,BAD_PHASE /* unknown phase - signal driver */ 348 jmp ITloop /* Try reading the bus again. */ 349 350p_dataout: 351 mvi DMAPARAMS,0x7d /* 352 * WIDEODD|SCSIEN|SDMAEN|HDMAEN| 353 * DIRECTION|FIFORESET 354 */ 355 jmp data_phase_init 356 357/* 358 * If we re-enter the data phase after going through another phase, the 359 * STCNT may have been cleared, so restore it from the residual field. 360 */ 361data_phase_reinit: 362 mvi DINDEX, STCNT0 363 mvi SCB_RESID_DCNT0 call bcopy_3 364 jmp data_phase_loop 365 366p_datain: 367 mvi DMAPARAMS,0x79 /* 368 * WIDEODD|SCSIEN|SDMAEN|HDMAEN| 369 * !DIRECTION|FIFORESET 370 */ 371data_phase_init: 372 call assert /* 373 * Ensure entering a data 374 * phase is okay - seen identify, etc. 375 */ 376 377 test FLAGS, DPHASE jnz data_phase_reinit 378 379 /* 380 * Initialize the DMA address and counter from the SCB. 381 * Also set SG_COUNT and SG_NEXT in memory since we cannot 382 * modify the values in the SCB itself until we see a 383 * save data pointers message. 384 */ 385 mvi DINDEX, HADDR0 386 mvi SCB_DATAPTR call bcopy_7 387 388 call set_stcnt_from_hcnt 389 390 mov SG_COUNT,SCB_SGCOUNT 391 392 mvi DINDEX, SG_NEXT 393 mvi SCB_SGPTR call bcopy_4 394 395 /* We have seen a data phase */ 396 or FLAGS, DPHASE 397 398data_phase_loop: 399/* Guard against overruns */ 400 test SG_COUNT, 0xff jnz data_phase_inbounds 401/* 402 * Turn on 'Bit Bucket' mode, set the transfer count to 403 * 16meg and let the target run until it changes phase. 404 * When the transfer completes, notify the host that we 405 * had an overrun. 406 */ 407 or SXFRCTL1,BITBUCKET 408 and DMAPARAMS, 0xf7 /* Turn off HDMAEN */ 409 mvi STCNT0,0xff 410 mvi STCNT1,0xff 411 mvi STCNT2,0xff 412 413data_phase_inbounds: 414/* If we are the last SG block, ensure wideodd is off. */ 415 cmp SG_COUNT,0x01 jne data_phase_wideodd 416 and DMAPARAMS, 0xbf /* Turn off WIDEODD */ 417data_phase_wideodd: 418 mov DMAPARAMS call dma 419 420/* Go tell the host about any overruns */ 421 test SXFRCTL1,BITBUCKET jnz data_phase_overrun 422 423/* Exit if we had an underrun */ 424 test SSTAT0,SDONE jz data_phase_finish /* underrun STCNT != 0 */ 425 426/* 427 * Advance the scatter-gather pointers if needed 428 */ 429sg_advance: 430 dec SG_COUNT /* one less segment to go */ 431 432 test SG_COUNT, 0xff jz data_phase_finish /* Are we done? */ 433 434 clr A /* add sizeof(struct scatter) */ 435 add SG_NEXT0,SG_SIZEOF,SG_NEXT0 436 adc SG_NEXT1,A,SG_NEXT1 437 438/* 439 * Load a struct scatter and set up the data address and length. 440 * If the working value of the SG count is nonzero, then 441 * we need to load a new set of values. 442 * 443 * This, like all DMA's, assumes little-endian host data storage. 444 */ 445sg_load: 446 clr HCNT2 447 clr HCNT1 448 mvi HCNT0,SG_SIZEOF 449 450 mvi DINDEX, HADDR0 451 mvi SG_NEXT0 call bcopy_4 452 453 or DFCNTRL,0xd /* HDMAEN|DIRECTION|FIFORESET */ 454 455 call dma_finish 456 457/* 458 * Copy data from FIFO into SCB data pointer and data count. This assumes 459 * that the SG segments are of the form: 460 * 461 * struct ahc_dma_seg { 462 * u_int32_t addr; four bytes, little-endian order 463 * u_int32_t len; four bytes, little endian order 464 * }; 465 */ 466 mvi HADDR0 call dfdat_in_7 467 468/* Load STCNT as well. It is a mirror of HCNT */ 469 call set_stcnt_from_hcnt 470 test SSTAT1,PHASEMIS jz data_phase_loop 471 472data_phase_finish: 473/* 474 * After a DMA finishes, save the SG and STCNT residuals back into the SCB 475 * We use STCNT instead of HCNT, since it's a reflection of how many bytes 476 * were transferred on the SCSI (as opposed to the host) bus. 477 */ 478 mov SCB_RESID_DCNT0,STCNT0 479 mov SCB_RESID_DCNT1,STCNT1 480 mov SCB_RESID_DCNT2,STCNT2 481 mov SCB_RESID_SGCNT, SG_COUNT 482 jmp ITloop 483 484data_phase_overrun: 485/* 486 * Turn off BITBUCKET mode and notify the host 487 */ 488 and SXFRCTL1,0x7f /* ~BITBUCKET */ 489 mvi INTSTAT,DATA_OVERRUN 490 jmp ITloop 491 492/* 493 * Command phase. Set up the DMA registers and let 'er rip. 494 */ 495p_command: 496 call assert 497 498/* 499 * Load HADDR and HCNT. 500 */ 501 mvi DINDEX, HADDR0 502 mvi SCB_CMDPTR call bcopy_5 503 clr HCNT1 504 clr HCNT2 505 506 call set_stcnt_from_hcnt 507 508 mvi DFCNTRL, 0x3d /* SCSIEN|SDMAEN|HDMAEN 509 * |DIRECTION|FIFORESET 510 */ 511p_command_dma: 512 test SSTAT0, SDONE jnz p_command_dma_done 513 test SSTAT1, PHASEMIS jz p_command_dma 514 test SSTAT0, SDONE jnz p_command_dma_done 515 clr DFCNTRL 516 jmp ITloop 517p_command_dma_done: 518 and DFCNTRL, 0xc7 /* ~(SCSIEN|SDMAEN|HDMAEN) */ 519p_command_dma_clear: 520 test DFCNTRL, 0x38 jnz p_command_dma_clear 521 jmp ITloop 522 523/* 524 * Status phase. Wait for the data byte to appear, then read it 525 * and store it into the SCB. 526 */ 527p_status: 528 call assert 529 530 mov SCB_TARGET_STATUS, SCSIDATL 531 jmp ITloop 532 533/* 534 * Message out phase. If there is not an active message, but the target 535 * took us into this phase anyway, build a no-op message and send it. 536 */ 537p_mesgout: 538 test MSG_LEN, 0xff jnz p_mesgout_start 539 mvi MSG_NOOP call mk_mesg /* build NOP message */ 540p_mesgout_start: 541/* 542 * Set up automatic PIO transfer from MSG0. Bit 3 in 543 * SXFRCTL0 (SPIOEN) is already on. 544 */ 545 mvi SINDEX,MSG0 546 mov DINDEX,MSG_LEN 547 548/* 549 * When target asks for a byte, drop ATN if it's the last one in 550 * the message. Otherwise, keep going until the message is exhausted. 551 * 552 * Keep an eye out for a phase change, in case the target issues 553 * a MESSAGE REJECT. 554 */ 555p_mesgout_loop: 556 /* 557 * If there is a parity error, wait for the kernel to 558 * see the interrupt and "update" our message response 559 * before continuing. 560 */ 561 test SSTAT1, REQINIT jz p_mesgout_loop 562 test SSTAT1, SCSIPERR jnz p_mesgout_loop 563 and LASTPHASE, PHASE_MASK, SCSISIGI 564 cmp LASTPHASE, P_MESGOUT jne p_mesgout_done 565/* 566 * If the next bus phase after ATN drops is a message out, it means 567 * that the target is requesting that the last message(s) be resent. 568 */ 569p_mesgout_testretry: 570 test DINDEX,0xff jnz p_mesgout_dropatn 571 or SCSISIGO,ATNO,LASTPHASE /* turn on ATN for the retry */ 572 jmp p_mesgout_start 573p_mesgout_dropatn: 574 cmp DINDEX,1 jne p_mesgout_outb /* last byte? */ 575 mvi CLRSINT1,CLRATNO /* drop ATN */ 576p_mesgout_outb: 577 dec DINDEX 578 mvi CLRSINT0, CLRSPIORDY 579 mov SCSIDATL,SINDIR 580 jmp p_mesgout_loop 581 582p_mesgout_done: 583 mvi CLRSINT1,CLRATNO /* Be sure to turn ATNO off */ 584 clr MSG_LEN /* no active msg */ 585 jmp ITloop 586 587/* 588 * Message in phase. Bytes are read using Automatic PIO mode. 589 */ 590p_mesgin: 591 mvi A call inb_first /* read the 1st message byte */ 592 mov REJBYTE,A /* save it for the driver */ 593 594 test A,MSG_IDENTIFYFLAG jnz mesgin_identify 595 cmp A,MSG_DISCONNECT je mesgin_disconnect 596 cmp A,MSG_SAVEDATAPOINTER je mesgin_sdptrs 597 cmp ALLZEROS,A je mesgin_complete 598 cmp A,MSG_RESTOREPOINTERS je mesgin_rdptrs 599 cmp A,MSG_EXTENDED je mesgin_extended 600 cmp A,MSG_MESSAGE_REJECT je mesgin_reject 601 602rej_mesgin: 603/* 604 * We have no idea what this message in is, so we issue a message reject 605 * and hope for the best. In any case, rejection should be a rare 606 * occurrence - signal the driver when it happens. 607 */ 608 mvi INTSTAT,SEND_REJECT /* let driver know */ 609 610 mvi MSG_MESSAGE_REJECT call mk_mesg 611 612mesgin_done: 613 call inb_last /*ack & turn auto PIO back on*/ 614 jmp ITloop 615 616 617mesgin_complete: 618/* 619 * We got a "command complete" message, so put the SCB_TAG into the QOUTFIFO, 620 * and trigger a completion interrupt. Before doing so, check to see if there 621 * is a residual or the status byte is something other than NO_ERROR (0). In 622 * either of these conditions, we upload the SCB back to the host so it can 623 * process this information. In the case of a non zero status byte, we 624 * additionally interrupt the kernel driver synchronously, allowing it to 625 * decide if sense should be retrieved. If the kernel driver wishes to request 626 * sense, it will fill the kernel SCB with a request sense command and set 627 * RETURN_1 to SEND_SENSE. If RETURN_1 is set to SEND_SENSE we redownload 628 * the SCB, and process it as the next command by adding it to the waiting list. 629 * If the kernel driver does not wish to request sense, it need only clear 630 * RETURN_1, and the command is allowed to complete normally. We don't bother 631 * to post to the QOUTFIFO in the error cases since it would require extra 632 * work in the kernel driver to ensure that the entry was removed before the 633 * command complete code tried processing it. 634 */ 635 636/* 637 * We expect to go to bus free after this message. 638 */ 639 and SIMODE1, 0xf7 /* ~ENBUSFREE */ 640/* 641 * First check for residuals 642 */ 643 test SCB_RESID_SGCNT,0xff jnz upload_scb 644 test SCB_TARGET_STATUS,0xff jz status_ok /* Good Status? */ 645upload_scb: 646 mvi DMAPARAMS, 0x9 /* HDMAEN | FIFORESET*/ 647 mov SCB_TAG call dma_scb 648check_status: 649 test SCB_TARGET_STATUS,0xff jz status_ok /* Just a residual? */ 650 mvi INTSTAT,BAD_STATUS /* let driver know */ 651 cmp RETURN_1, SEND_SENSE jne status_ok 652 /* This SCB becomes the next to execute as it will retrieve sense */ 653 mov SCB_LINKED_NEXT, SCB_TAG 654 jmp dma_next_scb 655 656status_ok: 657/* First, mark this target as free. */ 658 test SCB_CONTROL,TAG_ENB jnz complete /* 659 * Tagged commands 660 * don't busy the 661 * target. 662 */ 663 mov SAVED_SCBPTR, SCBPTR 664 mov SAVED_LINKPTR, SCB_LINKED_NEXT 665 mov SCB_TCL call index_untagged_scb 666 mov DINDIR, SAVED_LINKPTR 667 mov SCBPTR, SAVED_SCBPTR 668 669complete: 670 /* Post the SCB and issue an interrupt */ 671 mov QOUTFIFO,SCB_TAG 672 mvi INTSTAT,CMDCMPLT 673 674dma_next_scb: 675 cmp SCB_LINKED_NEXT, SCB_LIST_NULL je add_to_free_list 676 test FLAGS, PAGESCBS jnz dma_next_scb2 677 /* Only DMA on top of ourselves if we are the SCB to download */ 678 mov A, SCB_LINKED_NEXT 679 cmp SCB_TAG, A je dma_next_scb2 680 mov SCBPTR, A 681 jmp add_to_waiting_list 682dma_next_scb2: 683 mvi DMAPARAMS, 0xd /* HDMAEN|DIRECTION|FIFORESET */ 684 mov SCB_LINKED_NEXT call dma_scb 685add_to_waiting_list: 686 mov SCB_NEXT,WAITING_SCBH 687 mov WAITING_SCBH, SCBPTR 688 jmp mesgin_done 689add_to_free_list: 690 call add_scb_to_free_list 691 jmp mesgin_done 692 693/* 694 * Is it an extended message? Copy the message to our message buffer and 695 * notify the host. The host will tell us whether to reject this message, 696 * respond to it with the message that the host placed in our message buffer, 697 * or simply to do nothing. 698 */ 699mesgin_extended: 700 mvi MSGIN_EXT_LEN call inb_next 701 mov A, MSGIN_EXT_LEN 702mesgin_extended_loop: 703 mov DINDEX call inb_next 704 dec A 705 cmp DINDEX, MSGIN_EXT_LASTBYTE jne mesgin_extended_loop_test 706 dec DINDEX /* dump by repeatedly filling the last byte */ 707mesgin_extended_loop_test: 708 test A, 0xFF jnz mesgin_extended_loop 709mesgin_extended_intr: 710 mvi INTSTAT,EXTENDED_MSG /* let driver know */ 711 cmp RETURN_1,SEND_REJ je rej_mesgin 712 cmp RETURN_1,SEND_MSG jne mesgin_done 713/* The kernel has setup a message to be sent */ 714 or SCSISIGO,ATNO,LASTPHASE /* turn on ATNO */ 715 jmp mesgin_done 716 717/* 718 * Is it a disconnect message? Set a flag in the SCB to remind us 719 * and await the bus going free. 720 */ 721mesgin_disconnect: 722 and SIMODE1, 0xf7 /* ~ENBUSFREE */ 723 or SCB_CONTROL,DISCONNECTED 724 test FLAGS, PAGESCBS jz mesgin_done 725 call add_scb_to_disc_list 726 jmp mesgin_done 727 728/* 729 * Save data pointers message: 730 * Copying RAM values back to SCB, for Save Data Pointers message, but 731 * only if we've actually been into a data phase to change them. This 732 * protects against bogus data in scratch ram and the residual counts 733 * since they are only initialized when we go into data_in or data_out. 734 */ 735mesgin_sdptrs: 736 test FLAGS, DPHASE jz mesgin_done 737 mov SCB_SGCOUNT,SG_COUNT 738 739 /* The SCB SGPTR becomes the next one we'll download */ 740 mvi DINDEX, SCB_SGPTR 741 mvi SG_NEXT0 call bcopy_4 742 743 /* The SCB DATAPTR0 becomes the current SHADDR */ 744 mvi DINDEX, SCB_DATAPTR0 745 mvi SHADDR0 call bcopy_4 746 747/* 748 * Use the residual number since STCNT is corrupted by any message transfer. 749 */ 750 mvi SCB_RESID_DCNT0 call bcopy_3 751 752 jmp mesgin_done 753 754/* 755 * Restore pointers message? Data pointers are recopied from the 756 * SCB anytime we enter a data phase for the first time, so all 757 * we need to do is clear the DPHASE flag and let the data phase 758 * code do the rest. 759 */ 760mesgin_rdptrs: 761 and FLAGS,0xef /* 762 * !DPHASE we'll reload them 763 * the next time through 764 */ 765 jmp mesgin_done 766 767/* 768 * Identify message? For a reconnecting target, this tells us the lun 769 * that the reconnection is for - find the correct SCB and switch to it, 770 * clearing the "disconnected" bit so we don't "find" it by accident later. 771 */ 772mesgin_identify: 773 test A,0x78 jnz rej_mesgin /*!DiscPriv|!LUNTAR|!Reserved*/ 774 and A,0x07 /* lun in lower three bits */ 775 or SAVED_TCL,A /* SAVED_TCL should be complete now */ 776 call inb_last /* ACK */ 777 778/* 779 * Here we "snoop" the bus looking for a SIMPLE QUEUE TAG message. 780 * If we get one, we use the tag returned to switch to find the proper 781 * SCB. With SCB paging, this requires using findSCB for both tagged 782 * and non-tagged transactions since the SCB may exist in any slot. 783 * If we're not using SCB paging, we can use the tag as the direct 784 * index to the SCB. 785 */ 786 mvi ARG_1,SCB_LIST_NULL /* Default to no-tag */ 787snoop_tag_loop: 788 test SSTAT1,REQINIT jz snoop_tag_loop 789 and LASTPHASE, PHASE_MASK, SCSISIGI 790 cmp LASTPHASE, P_MESGIN, jne use_findSCB 791 mvi A call inb_first 792 cmp A,MSG_SIMPLE_Q_TAG jne use_findSCB 793get_tag: 794 or FLAGS, TAGGED_SCB 795 mvi ARG_1 call inb_next /* tag value */ 796/* 797 * See if the tag is in range. The tag is < SCBCOUNT if we add 798 * the complement of SCBCOUNT to the incomming tag and there is 799 * no carry. 800 */ 801 mov A,COMP_SCBCOUNT 802 add SINDEX,A,ARG_1 803 jc send_abort_msg 804 805/* 806 * Ensure that the SCB the tag points to is for an SCB transaction 807 * to the reconnecting target. 808 */ 809 test FLAGS, PAGESCBS jz index_by_tag 810use_findSCB: 811 mov ALLZEROS call findSCB /* Have to search */ 812 cmp SINDEX, SCB_LIST_NULL, je not_found 813setup_SCB: 814 and SCB_CONTROL,0xfb /* clear disconnect bit in SCB */ 815 or FLAGS,IDENTIFY_SEEN /* make note of IDENTIFY */ 816 test SCB_CONTROL,TAG_ENB jnz mesgin_done /* Ack Tag */ 817 jmp ITloop 818index_by_tag: 819 mov SCBPTR,ARG_1 820 mov A, SAVED_TCL 821 cmp SCB_TCL,A jne send_abort_msg 822 test SCB_CONTROL,TAG_ENB jz send_abort_msg 823 jmp setup_SCB 824 825not_found: 826 mvi INTSTAT, NO_MATCH 827send_abort_msg: 828 test FLAGS, TAGGED_SCB jnz abort_tag_msg 829 mvi MSG_ABORT call mk_mesg 830 jmp mesgin_done 831abort_tag_msg: 832 mvi MSG_ABORT_TAG call mk_mesg /* ABORT TAG message */ 833 jmp mesgin_done 834 835/* 836 * Message reject? Let the kernel driver handle this. If we have an 837 * outstanding WDTR or SDTR negotiation, assume that it's a response from 838 * the target selecting 8bit or asynchronous transfer, otherwise just ignore 839 * it since we have no clue what it pertains to. 840 */ 841mesgin_reject: 842 mvi INTSTAT, REJECT_MSG 843 jmp mesgin_done 844 845/* 846 * [ ADD MORE MESSAGE HANDLING HERE ] 847 */ 848 849/* 850 * Locking the driver out, build a one-byte message passed in SINDEX 851 * if there is no active message already. SINDEX is returned intact. 852 */ 853mk_mesg: 854 mvi SEQCTL,0x50 /* PAUSEDIS|FASTMODE */ 855 test MSG_LEN,0xff jz mk_mesg1 /* Should always succeed */ 856 857 /* 858 * Hmmm. For some reason the mesg buffer is in use. 859 * Tell the driver. It should look at SINDEX to find 860 * out what we wanted to use the buffer for and resolve 861 * the conflict. 862 */ 863 mvi SEQCTL,0x10 /* !PAUSEDIS|FASTMODE */ 864 mvi INTSTAT,MSG_BUFFER_BUSY 865 866mk_mesg1: 867 or SCSISIGO,ATNO,LASTPHASE /* turn on ATNO */ 868 mvi MSG_LEN,1 /* length = 1 */ 869 mov MSG0,SINDEX /* 1-byte message */ 870 mvi SEQCTL,0x10 ret /* !PAUSEDIS|FASTMODE */ 871 872/* 873 * Functions to read data in Automatic PIO mode. 874 * 875 * According to Adaptec's documentation, an ACK is not sent on input from 876 * the target until SCSIDATL is read from. So we wait until SCSIDATL is 877 * latched (the usual way), then read the data byte directly off the bus 878 * using SCSIBUSL. When we have pulled the ATN line, or we just want to 879 * acknowledge the byte, then we do a dummy read from SCISDATL. The SCSI 880 * spec guarantees that the target will hold the data byte on the bus until 881 * we send our ACK. 882 * 883 * The assumption here is that these are called in a particular sequence, 884 * and that REQ is already set when inb_first is called. inb_{first,next} 885 * use the same calling convention as inb. 886 */ 887 888inb_next: 889 mov NONE,SCSIDATL /*dummy read from latch to ACK*/ 890inb_next_wait: 891 /* 892 * If there is a parity error, wait for the kernel to 893 * see the interrupt and prepare our message response 894 * before continuing. 895 */ 896 test SSTAT1, REQINIT jz inb_next_wait 897 test SSTAT1, SCSIPERR jnz inb_next_wait 898 and LASTPHASE, PHASE_MASK, SCSISIGI 899 cmp LASTPHASE, P_MESGIN jne mesgin_phasemis 900inb_first: 901 mov DINDEX,SINDEX 902 mov DINDIR,SCSIBUSL ret /*read byte directly from bus*/ 903inb_last: 904 mov NONE,SCSIDATL ret /*dummy read from latch to ACK*/ 905 906mesgin_phasemis: 907/* 908 * We expected to receive another byte, but the target changed phase 909 */ 910 mvi INTSTAT, MSGIN_PHASEMIS 911 jmp ITloop 912 913/* 914 * DMA data transfer. HADDR and HCNT must be loaded first, and 915 * SINDEX should contain the value to load DFCNTRL with - 0x3d for 916 * host->scsi, or 0x39 for scsi->host. The SCSI channel is cleared 917 * during initialization. 918 */ 919dma: 920 mov DFCNTRL,SINDEX 921dma1: 922 test SSTAT0,DMADONE jnz dma3 923 test SSTAT1,PHASEMIS jz dma1 /* ie. underrun */ 924 925/* 926 * We will be "done" DMAing when the transfer count goes to zero, or 927 * the target changes the phase (in light of this, it makes sense that 928 * the DMA circuitry doesn't ACK when PHASEMIS is active). If we are 929 * doing a SCSI->Host transfer, the data FIFO should be flushed auto- 930 * magically on STCNT=0 or a phase change, so just wait for FIFO empty 931 * status. 932 */ 933dma3: 934 test SINDEX,DIRECTION jnz dma5 935dma4: 936 test DFSTATUS,FIFOEMP jz dma4 937 938/* 939 * Now shut the DMA enables off and make sure that the DMA enables are 940 * actually off first lest we get an ILLSADDR. 941 */ 942dma5: 943 /* Don't clobber an inprogress host data transfer */ 944 test DFSTATUS, MREQPEND jnz dma5 945 /* disable DMA */ 946 and DFCNTRL, 0xc7 /* ~(SCSIEN|SDMAEN|HDMAEN|DIRECTION) */ 947dma6: 948 test DFCNTRL, HDMAENACK jnz dma6 949return: 950 ret 951 952/* 953 * Common SCSI initialization for selection and reselection. Expects 954 * the target SCSI ID to be in the upper four bits of SINDEX, and A's 955 * contents are stomped on return. 956 */ 957initialize_scsiid: 958 and SINDEX,0xf0 /* Get target ID */ 959 mov SAVED_TCL, SINDEX /* Update the target portion of this */ 960 and A,0x0f,SCSIID 961 or SINDEX,A 962 mov SCSIID,SINDEX ret 963 964/* 965 * Assert that if we've been reselected, then we've seen an IDENTIFY 966 * message. 967 */ 968assert: 969 test FLAGS,RESELECTED jz return /* reselected? */ 970 test FLAGS,IDENTIFY_SEEN jnz return /* seen IDENTIFY? */ 971 972 mvi INTSTAT,NO_IDENT ret /* no - tell the kernel */ 973 974/* 975 * Locate a disconnected SCB either by SAVED_TCL (ARG_1 is SCB_LIST_NULL) 976 * or by the SCBIDn ARG_1. The search begins at the SCB index passed in 977 * via SINDEX. If the SCB cannot be found, SINDEX will be SCB_LIST_NULL, 978 * otherwise, SCBPTR is set to the proper SCB. 979 */ 980findSCB: 981 mov SCBPTR,SINDEX /* switch to next SCB */ 982 test SCB_CONTROL,DISCONNECTED jz findSCB1 /*should be disconnected*/ 983 cmp ARG_1, SCB_LIST_NULL jne findBySCBID 984 mov A, SAVED_TCL 985 cmp SCB_TCL,A je foundSCB /* target ID/channel/lun match? */ 986findSCB1: 987 inc SINDEX 988 mov A,SCBCOUNT 989 cmp SINDEX,A jne findSCB 990/* 991 * We didn't find it. If we're paging, pull an SCB and DMA down the 992 * one we want. If we aren't paging or the SCB we dma down has the 993 * abort flag set, return not found. 994 */ 995 test FLAGS, PAGESCBS jz find_error 996 mov ALLZEROS call get_free_or_disc_scb 997 cmp ARG_1, SCB_LIST_NULL jne find_dma_scb 998 mov SAVED_TCL call index_untagged_scb 999 mov ARG_1, SINDIR /* SCBID of SCB to fetch */ 1000find_dma_scb: 1001 mvi DMAPARAMS, 0xd /* HDMAEN|DIRECTION|FIFORESET */ 1002 mov ARG_1 call dma_scb 1003 test SCB_CONTROL, ABORT_SCB jz return 1004find_error: 1005 mvi SINDEX, SCB_LIST_NULL ret 1006findBySCBID: 1007 mov A, ARG_1 /* Tag passed in ARG_1 */ 1008 cmp SCB_TAG,A jne findSCB1 /* Found it? */ 1009foundSCB: 1010 test SCB_CONTROL, ABORT_SCB jnz find_error 1011 test FLAGS,PAGESCBS jz return 1012rem_scb_from_disc_list: 1013/* Remove this SCB from the disconnection list */ 1014 cmp SCB_NEXT,SCB_LIST_NULL je unlink_prev 1015 mov SAVED_LINKPTR, SCB_PREV 1016 mov SCBPTR, SCB_NEXT 1017 mov SCB_PREV, SAVED_LINKPTR 1018 mov SCBPTR, SINDEX 1019unlink_prev: 1020 cmp SCB_PREV,SCB_LIST_NULL je rHead/* At the head of the list */ 1021 mov SAVED_LINKPTR, SCB_NEXT 1022 mov SCBPTR, SCB_PREV 1023 mov SCB_NEXT, SAVED_LINKPTR 1024 mov SCBPTR, SINDEX ret 1025rHead: 1026 mov DISCONNECTED_SCBH,SCB_NEXT ret 1027 1028set_stcnt_from_hcnt: 1029 mov STCNT0, HCNT0 1030 mov STCNT1, HCNT1 1031 mov STCNT2, HCNT2 ret 1032 1033bcopy_7: 1034 mov DINDIR, SINDIR 1035 mov DINDIR, SINDIR 1036bcopy_5: 1037 mov DINDIR, SINDIR 1038bcopy_4: 1039 mov DINDIR, SINDIR 1040bcopy_3: 1041 mov DINDIR, SINDIR 1042 mov DINDIR, SINDIR 1043 mov DINDIR, SINDIR ret 1044 1045dma_scb: 1046 /* 1047 * SCB index is in SINDEX. Determine the physical address in 1048 * the host where this SCB is located and load HADDR with it. 1049 */ 1050 shr DINDEX, SINDEX, 3 1051 shl A, SINDEX, 5 1052 add HADDR0, A, HSCB_ADDR0 1053 mov A, DINDEX 1054 adc HADDR1, A, HSCB_ADDR1 1055 clr A 1056 adc HADDR2, A, HSCB_ADDR2 1057 adc HADDR3, A, HSCB_ADDR3 1058 /* Setup Count */ 1059 mvi HCNT0, 28 1060 clr HCNT1 1061 clr HCNT2 1062 mov DFCNTRL, DMAPARAMS 1063 test DMAPARAMS, DIRECTION jnz dma_scb_fromhost 1064 /* Fill it with the SCB data */ 1065 call copy_scb_tofifo 1066 mvi DFCNTRL, 0xa /* HDMAEN | FIFOFLUSH */ 1067dma_scb_fromhost: 1068 call dma_finish 1069 /* If we were putting the SCB, we are done */ 1070 test DMAPARAMS, DIRECTION jz return 1071 mvi SCBARRAY call dfdat_in_7 1072 call dfdat_in_7_continued 1073 call dfdat_in_7_continued 1074 jmp dfdat_in_7_continued 1075dfdat_in_7: 1076 mov DINDEX,SINDEX 1077dfdat_in_7_continued: 1078 mov DINDIR,DFDAT 1079 mov DINDIR,DFDAT 1080 mov DINDIR,DFDAT 1081 mov DINDIR,DFDAT 1082 mov DINDIR,DFDAT 1083 mov DINDIR,DFDAT 1084 mov DINDIR,DFDAT ret 1085 1086copy_scb_tofifo: 1087 mvi SCBARRAY call dfdat_out_7 1088 call dfdat_out_7 1089 call dfdat_out_7 1090dfdat_out_7: 1091 mov DFDAT,SINDIR 1092 mov DFDAT,SINDIR 1093 mov DFDAT,SINDIR 1094 mov DFDAT,SINDIR 1095 mov DFDAT,SINDIR 1096 mov DFDAT,SINDIR 1097 mov DFDAT,SINDIR ret 1098 1099/* 1100 * Wait for DMA from host memory to data FIFO to complete, then disable 1101 * DMA and wait for it to acknowledge that it's off. 1102 */ 1103dma_finish: 1104 test DFSTATUS,HDONE jz dma_finish 1105 /* Turn off DMA preserving WIDEODD */ 1106 and DFCNTRL,WIDEODD 1107dma_finish2: 1108 test DFCNTRL,HDMAENACK jnz dma_finish2 1109 ret 1110 1111index_untagged_scb: 1112 mov DINDEX, SINDEX 1113 shr DINDEX, 4 1114 and DINDEX, 0x03 /* Bottom two bits of tid */ 1115 add DINDEX, SCB_ACTIVE0 1116 shr A, SINDEX, 6 /* Target ID divided by 4 */ 1117 test SINDEX, SELBUSB jz index_untagged_scb2 1118 add A, 2 /* Add 2 positions */ 1119index_untagged_scb2: 1120 mov SCBPTR, A /* 1121 * Select the SCB with this 1122 * target's information. 1123 */ 1124 mov SINDEX, DINDEX ret 1125 1126 1127get_free_or_disc_scb: 1128 cmp FREE_SCBH, SCB_LIST_NULL jne dequeue_free_scb 1129 cmp DISCONNECTED_SCBH, SCB_LIST_NULL jne dequeue_disc_scb 1130return_error: 1131 mvi SINDEX, SCB_LIST_NULL ret 1132dequeue_disc_scb: 1133 mov SCBPTR, DISCONNECTED_SCBH 1134/* 1135 * If we have a residual, then we are in the middle of some I/O 1136 * and we have to send this SCB back up to the kernel so that the 1137 * saved data pointers and residual information isn't lost. 1138 */ 1139 test SCB_RESID_SGCNT,0xff jz unlink_disc_scb 1140 mvi DMAPARAMS, 0x9 /* HDMAEN | FIFORESET*/ 1141 mov SCB_TAG call dma_scb 1142unlink_disc_scb: 1143 /* jmp instead of call since we want to return anyway */ 1144 mov SCBPTR jmp rem_scb_from_disc_list 1145dequeue_free_scb: 1146 mov SCBPTR, FREE_SCBH 1147 mov FREE_SCBH, SCB_NEXT ret 1148 1149add_scb_to_free_list: 1150 mov SCB_NEXT, FREE_SCBH 1151 mov FREE_SCBH, SCBPTR ret 1152 1153add_scb_to_disc_list: 1154/* 1155 * Link this SCB into the DISCONNECTED list. This list holds the 1156 * candidates for paging out an SCB if one is needed for a new command. 1157 * Modifying the disconnected list is a critical(pause dissabled) section. 1158 */ 1159 mvi SCB_PREV, SCB_LIST_NULL 1160 mov SCB_NEXT, DISCONNECTED_SCBH 1161 mov DISCONNECTED_SCBH, SCBPTR 1162 cmp SCB_NEXT,SCB_LIST_NULL je return 1163 mov SCBPTR,SCB_NEXT 1164 mov SCB_PREV,DISCONNECTED_SCBH 1165 mov SCBPTR,DISCONNECTED_SCBH ret 1166 1167