src/firmware/scsi.c

   1 //      Copyright (C) 2014 Michael McMaster <michael@codesrc.com>
   2 //
   3 //      This file is part of SCSI2SD.
   4 //
   5 //      SCSI2SD is free software: you can redistribute it and/or modify
   6 //      it under the terms of the GNU General Public License as published by
   7 //      the Free Software Foundation, either version 3 of the License, or
   8 //      (at your option) any later version.
   9 //
  10 //      SCSI2SD is distributed in the hope that it will be useful,
  11 //      but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 //      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 //      GNU General Public License for more details.
  14 //
  15 //      You should have received a copy of the GNU General Public License
  16 //      along with SCSI2SD.  If not, see <http://www.gnu.org/licenses/>.
  17
  18 #include "scsi.h"
  19 #include "scsiPhy.h"
  20 #include "config.h"
  21 #include "diagnostic.h"
  22 #include "disk.h"
  23 #include "inquiry.h"
  24 #include "led.h"
  25 #include "mode.h"
  26 #include "time.h"
  27 #include "bsp.h"
  28 #include "cdrom.h"
  29 //#include "debug.h"
  30 #include "tape.h"
  31 #include "mo.h"
  32
  33 #include <string.h>
  34
  35 // Global SCSI device state.
  36 ScsiDevice scsiDev S2S_DMA_ALIGN;
  37
  38 static void enter_SelectionPhase(void);
  39 static void process_SelectionPhase(void);
  40 static void enter_BusFree(void);
  41 static void enter_MessageIn(uint8_t message);
  42 static void enter_Status(uint8_t status);
  43 static void enter_DataIn(int len);
  44 static void process_DataIn(void);
  45 static void process_DataOut(void);
  46 static void process_Command(void);
  47
  48 static void doReserveRelease(void);
  49
  50 static void enter_BusFree()
  51 {
  52         // This delay probably isn't needed for most SCSI hosts, but it won't
  53         // hurt either. It's possible some of the samplers needed this delay.
  54         if (scsiDev.compatMode < COMPAT_SCSI2)
  55         {
  56                 s2s_delay_us(2);
  57         }
  58
  59 #if 0
  60         if (scsiDev.status != GOOD && isDebugEnabled())
  61         {
  62                 // We want to capture debug information for failure cases.
  63                 s2s_delay_ms(64);
  64         }
  65 #endif
  66
  67         scsiEnterBusFree();
  68
  69         // Wait for the initiator to cease driving signals
  70         // Bus settle delay + bus clear delay = 1200ns
  71         s2s_delay_us(2);
  72
  73
  74         s2s_ledOff();
  75         scsiDev.phase = BUS_FREE;
  76 }
  77
  78 static void enter_MessageIn(uint8_t message)
  79 {
  80         scsiDev.msgIn = message;
  81         scsiDev.phase = MESSAGE_IN;
  82 }
  83
  84 void process_MessageIn()
  85 {
  86         scsiEnterPhase(MESSAGE_IN);
  87         scsiWriteByte(scsiDev.msgIn);
  88
  89         if (unlikely(scsiDev.atnFlag))
  90         {
  91                 // If there was a parity error, we go
  92                 // back to MESSAGE_OUT first, get out parity error message, then come
  93                 // back here.
  94         }
  95         else if ((scsiDev.msgIn == MSG_LINKED_COMMAND_COMPLETE) ||
  96                 (scsiDev.msgIn == MSG_LINKED_COMMAND_COMPLETE_WITH_FLAG))
  97         {
  98                 // Go back to the command phase and start again.
  99                 scsiDev.phase = COMMAND;
 100                 scsiDev.parityError = 0;
 101                 scsiDev.dataPtr = 0;
 102                 scsiDev.savedDataPtr = 0;
 103                 scsiDev.dataLen = 0;
 104                 scsiDev.status = GOOD;
 105                 transfer.blocks = 0;
 106                 transfer.currentBlock = 0;
 107         }
 108         else /*if (scsiDev.msgIn == MSG_COMMAND_COMPLETE)*/
 109         {
 110                 enter_BusFree();
 111         }
 112 }
 113
 114 static void messageReject()
 115 {
 116         scsiEnterPhase(MESSAGE_IN);
 117         scsiWriteByte(MSG_REJECT);
 118 }
 119
 120 static void enter_Status(uint8_t status)
 121 {
 122         scsiDev.status = status;
 123         scsiDev.phase = STATUS;
 124
 125         scsiDev.lastStatus = scsiDev.status;
 126         scsiDev.lastSense = scsiDev.target->sense.code;
 127         scsiDev.lastSenseASC = scsiDev.target->sense.asc;
 128 }
 129
 130 void process_Status()
 131 {
 132         scsiEnterPhase(STATUS);
 133
 134         uint8_t message;
 135
 136         uint8_t control = scsiDev.cdb[scsiDev.cdbLen - 1];
 137         if ((scsiDev.status == GOOD) && (control & 0x01))
 138         {
 139                 // Linked command.
 140                 scsiDev.status = INTERMEDIATE;
 141                 if (control & 0x02)
 142                 {
 143                         message = MSG_LINKED_COMMAND_COMPLETE_WITH_FLAG;
 144                 }
 145                 else
 146                 {
 147                         message = MSG_LINKED_COMMAND_COMPLETE;
 148                 }
 149         }
 150         else
 151         {
 152                 message = MSG_COMMAND_COMPLETE;
 153         }
 154         scsiWriteByte(scsiDev.status);
 155
 156         scsiDev.lastStatus = scsiDev.status;
 157         scsiDev.lastSense = scsiDev.target->sense.code;
 158         scsiDev.lastSenseASC = scsiDev.target->sense.asc;
 159
 160         // Command Complete occurs AFTER a valid status has been
 161         // sent. then we go bus-free.
 162         enter_MessageIn(message);
 163 }
 164
 165 static void enter_DataIn(int len)
 166 {
 167         scsiDev.dataLen = len;
 168         scsiDev.phase = DATA_IN;
 169 }
 170
 171 static void process_DataIn()
 172 {
 173         uint32_t len;
 174
 175         if (scsiDev.dataLen > sizeof(scsiDev.data))
 176         {
 177                 scsiDev.dataLen = sizeof(scsiDev.data);
 178         }
 179
 180         len = scsiDev.dataLen - scsiDev.dataPtr;
 181         if (len > 0)
 182         {
 183                 scsiEnterPhase(DATA_IN);
 184                 scsiWrite(scsiDev.data + scsiDev.dataPtr, len);
 185                 scsiDev.dataPtr += len;
 186         }
 187
 188         if ((scsiDev.dataPtr >= scsiDev.dataLen) &&
 189                 (transfer.currentBlock == transfer.blocks))
 190         {
 191                 enter_Status(GOOD);
 192         }
 193 }
 194
 195 static void process_DataOut()
 196 {
 197         uint32_t len;
 198
 199         if (scsiDev.dataLen > sizeof(scsiDev.data))
 200         {
 201                 scsiDev.dataLen = sizeof(scsiDev.data);
 202         }
 203
 204         scsiDev.parityError = 0;
 205         len = scsiDev.dataLen - scsiDev.dataPtr;
 206         if (len > 0)
 207         {
 208                 scsiEnterPhase(DATA_OUT);
 209
 210                 scsiRead(scsiDev.data + scsiDev.dataPtr, len);
 211                 scsiDev.dataPtr += len;
 212
 213                 if (scsiDev.parityError &&
 214                         (scsiDev.boardCfg.flags & S2S_CFG_ENABLE_PARITY) &&
 215                         (scsiDev.compatMode >= COMPAT_SCSI2))
 216                 {
 217                         scsiDev.target->sense.code = ABORTED_COMMAND;
 218                         scsiDev.target->sense.asc = SCSI_PARITY_ERROR;
 219                         enter_Status(CHECK_CONDITION);
 220                 }
 221         }
 222
 223         if ((scsiDev.dataPtr >= scsiDev.dataLen) &&
 224                 (transfer.currentBlock == transfer.blocks))
 225         {
 226                 if (scsiDev.postDataOutHook != NULL)
 227                 {
 228                         scsiDev.postDataOutHook();
 229                 }
 230                 else
 231                 {
 232                         enter_Status(GOOD);
 233                 }
 234         }
 235 }
 236
 237 static const uint8_t CmdGroupBytes[8] = {6, 10, 10, 6, 6, 12, 6, 6};
 238 static void process_Command()
 239 {
 240         int group;
 241         uint8_t command;
 242         uint8_t control;
 243
 244         scsiEnterPhase(COMMAND);
 245         scsiDev.parityError = 0;
 246
 247         memset(scsiDev.cdb + 6, 0, sizeof(scsiDev.cdb) - 6);
 248         scsiRead(scsiDev.cdb, 6);
 249
 250         group = scsiDev.cdb[0] >> 5;
 251         scsiDev.cdbLen = CmdGroupBytes[group];
 252         if (scsiDev.cdbLen - 6 > 0)
 253         {
 254                 scsiRead(scsiDev.cdb + 6, scsiDev.cdbLen - 6);
 255         }
 256
 257         command = scsiDev.cdb[0];
 258
 259         // Prefer LUN's set by IDENTIFY messages for newer hosts.
 260         if (scsiDev.lun < 0)
 261         {
 262                 scsiDev.lun = scsiDev.cdb[1] >> 5;
 263         }
 264
 265         control = scsiDev.cdb[scsiDev.cdbLen - 1];
 266
 267         scsiDev.cmdCount++;
 268         const S2S_TargetCfg* cfg = scsiDev.target->cfg;
 269
 270         if (unlikely(scsiDev.resetFlag))
 271         {
 272                 // Don't log bogus commands
 273                 scsiDev.cmdCount--;
 274                 memset(scsiDev.cdb, 0xff, sizeof(scsiDev.cdb));
 275                 return;
 276         }
 277         else if (scsiDev.parityError &&
 278                 (scsiDev.boardCfg.flags & S2S_CFG_ENABLE_PARITY) &&
 279                 (scsiDev.compatMode >= COMPAT_SCSI2))
 280         {
 281                 scsiDev.target->sense.code = ABORTED_COMMAND;
 282                 scsiDev.target->sense.asc = SCSI_PARITY_ERROR;
 283                 enter_Status(CHECK_CONDITION);
 284         }
 285         else if ((control & 0x02) && ((control & 0x01) == 0))
 286         {
 287                 // FLAG set without LINK flag.
 288                 scsiDev.target->sense.code = ILLEGAL_REQUEST;
 289                 scsiDev.target->sense.asc = INVALID_FIELD_IN_CDB;
 290                 enter_Status(CHECK_CONDITION);
 291         }
 292         else if (command == 0x12)
 293         {
 294                 s2s_scsiInquiry();
 295         }
 296         else if (command == 0x03)
 297         {
 298                 // REQUEST SENSE
 299                 uint32_t allocLength = scsiDev.cdb[4];
 300
 301                 // As specified by the SASI and SCSI1 standard.
 302                 // Newer initiators won't be specifying 0 anyway.
 303                 if (allocLength == 0) allocLength = 4;
 304
 305                 memset(scsiDev.data, 0, 256); // Max possible alloc length
 306                 scsiDev.data[0] = 0xF0;
 307                 scsiDev.data[2] = scsiDev.target->sense.code & 0x0F;
 308
 309                 scsiDev.data[3] = transfer.lba >> 24;
 310                 scsiDev.data[4] = transfer.lba >> 16;
 311                 scsiDev.data[5] = transfer.lba >> 8;
 312                 scsiDev.data[6] = transfer.lba;
 313
 314                 // Additional bytes if there are errors to report
 315                 scsiDev.data[7] = 10; // additional length
 316                 scsiDev.data[12] = scsiDev.target->sense.asc >> 8;
 317                 scsiDev.data[13] = scsiDev.target->sense.asc;
 318
 319                 // Silently truncate results. SCSI-2 spec 8.2.14.
 320                 enter_DataIn(allocLength);
 321
 322                 // This is a good time to clear out old sense information.
 323                 scsiDev.target->sense.code = NO_SENSE;
 324                 scsiDev.target->sense.asc = NO_ADDITIONAL_SENSE_INFORMATION;
 325         }
 326         // Some old SCSI drivers do NOT properly support
 327         // unitAttention. eg. the Mac Plus would trigger a SCSI reset
 328         // on receiving the unit attention response on boot, thus
 329         // triggering another unit attention condition.
 330         else if (scsiDev.target->unitAttention &&
 331                 (scsiDev.boardCfg.flags & S2S_CFG_ENABLE_UNIT_ATTENTION))
 332         {
 333                 scsiDev.target->sense.code = UNIT_ATTENTION;
 334                 scsiDev.target->sense.asc = scsiDev.target->unitAttention;
 335
 336                 // If initiator doesn't do REQUEST SENSE for the next command, then
 337                 // data is lost.
 338                 scsiDev.target->unitAttention = 0;
 339
 340                 enter_Status(CHECK_CONDITION);
 341         }
 342         else if (scsiDev.lun)
 343         {
 344                 scsiDev.target->sense.code = ILLEGAL_REQUEST;
 345                 scsiDev.target->sense.asc = LOGICAL_UNIT_NOT_SUPPORTED;
 346                 enter_Status(CHECK_CONDITION);
 347         }
 348         else if (command == 0x17 || command == 0x16)
 349         {
 350                 doReserveRelease();
 351         }
 352         else if ((scsiDev.target->reservedId >= 0) &&
 353                 (scsiDev.target->reservedId != scsiDev.initiatorId))
 354         {
 355                 enter_Status(CONFLICT);
 356         }
 357         // Handle odd device types first that may override basic read and
 358         // write commands. Will fall-through to generic disk handling.
 359         else if (((cfg->deviceType == S2S_CFG_OPTICAL) && scsiCDRomCommand()) ||
 360                 ((cfg->deviceType == S2S_CFG_SEQUENTIAL) && scsiTapeCommand()) ||
 361                 ((cfg->deviceType == S2S_CFG_MO) && scsiMOCommand()))
 362         {
 363                 // Already handled.
 364         }
 365         else if (scsiDiskCommand())
 366         {
 367                 // Already handled.
 368                 // check for the performance-critical read/write
 369                 // commands ASAP.
 370         }
 371         else if (command == 0x1C)
 372         {
 373                 scsiReceiveDiagnostic();
 374         }
 375         else if (command == 0x1D)
 376         {
 377                 scsiSendDiagnostic();
 378         }
 379         else if (command == 0x3B)
 380         {
 381                 scsiWriteBuffer();
 382         }
 383         else if (command == 0x3C)
 384         {
 385                 scsiReadBuffer();
 386         }
 387         else if (!scsiModeCommand())
 388         {
 389                 scsiDev.target->sense.code = ILLEGAL_REQUEST;
 390                 scsiDev.target->sense.asc = INVALID_COMMAND_OPERATION_CODE;
 391                 enter_Status(CHECK_CONDITION);
 392         }
 393
 394         // Successful
 395         if (scsiDev.phase == COMMAND) // No status set, and not in DATA_IN
 396         {
 397                 enter_Status(GOOD);
 398         }
 399
 400 }
 401
 402 static void doReserveRelease()
 403 {
 404         int extentReservation = scsiDev.cdb[1] & 1;
 405         int thirdPty = scsiDev.cdb[1] & 0x10;
 406         int thirdPtyId = (scsiDev.cdb[1] >> 1) & 0x7;
 407         uint8_t command = scsiDev.cdb[0];
 408
 409         int canRelease =
 410                 (!thirdPty && (scsiDev.initiatorId == scsiDev.target->reservedId)) ||
 411                         (thirdPty &&
 412                                 (scsiDev.target->reserverId == scsiDev.initiatorId) &&
 413                                 (scsiDev.target->reservedId == thirdPtyId)
 414                         );
 415
 416         if (extentReservation)
 417         {
 418                 // Not supported.
 419                 scsiDev.target->sense.code = ILLEGAL_REQUEST;
 420                 scsiDev.target->sense.asc = INVALID_FIELD_IN_CDB;
 421                 enter_Status(CHECK_CONDITION);
 422         }
 423         else if (command == 0x17) // release
 424         {
 425                 if ((scsiDev.target->reservedId < 0) || canRelease)
 426                 {
 427                         scsiDev.target->reservedId = -1;
 428                         scsiDev.target->reserverId = -1;
 429                 }
 430                 else
 431                 {
 432                         enter_Status(CONFLICT);
 433                 }
 434         }
 435         else // assume reserve.
 436         {
 437                 if ((scsiDev.target->reservedId < 0) || canRelease)
 438                 {
 439                         scsiDev.target->reserverId = scsiDev.initiatorId;
 440                         if (thirdPty)
 441                         {
 442                                 scsiDev.target->reservedId = thirdPtyId;
 443                         }
 444                         else
 445                         {
 446                                 scsiDev.target->reservedId = scsiDev.initiatorId;
 447                         }
 448                 }
 449                 else
 450                 {
 451                         // Already reserved by someone else!
 452                         enter_Status(CONFLICT);
 453                 }
 454         }
 455 }
 456
 457 static void scsiReset()
 458 {
 459         scsiDev.rstCount++;
 460         s2s_ledOff();
 461
 462         scsiPhyReset();
 463
 464         scsiDev.parityError = 0;
 465         scsiDev.phase = BUS_FREE;
 466         scsiDev.atnFlag = 0;
 467         scsiDev.resetFlag = 0;
 468         scsiDev.lun = -1;
 469         scsiDev.compatMode = COMPAT_UNKNOWN;
 470
 471         if (scsiDev.target)
 472         {
 473                 if (scsiDev.target->unitAttention != POWER_ON_RESET)
 474                 {
 475                         scsiDev.target->unitAttention = SCSI_BUS_RESET;
 476                 }
 477                 scsiDev.target->reservedId = -1;
 478                 scsiDev.target->reserverId = -1;
 479                 scsiDev.target->sense.code = NO_SENSE;
 480                 scsiDev.target->sense.asc = NO_ADDITIONAL_SENSE_INFORMATION;
 481         }
 482         scsiDev.target = NULL;
 483
 484         for (int i = 0; i < S2S_MAX_TARGETS; ++i)
 485         {
 486                 scsiDev.target[i].syncOffset = 0;
 487                 scsiDev.target[i].syncPeriod = 0;
 488         }
 489
 490         scsiDiskReset();
 491
 492         scsiDev.postDataOutHook = NULL;
 493
 494         // Sleep to allow the bus to settle down a bit.
 495         // We must be ready again within the "Reset to selection time" of
 496         // 250ms.
 497         // There is no guarantee that the RST line will be negated by then.
 498         // NOTE: We could be connected and powered by USB for configuration,
 499         // in which case TERMPWR cannot be supplied, and reset will ALWAYS
 500         // be true. Therefore, the sleep here must be slow to avoid slowing
 501         // USB comms
 502         s2s_delay_ms(1); // 1ms.
 503 }
 504
 505 static void enter_SelectionPhase()
 506 {
 507         // Ignore stale versions of this flag, but ensure we know the
 508         // current value if the flag is still set.
 509         scsiDev.atnFlag = 0;
 510         scsiDev.parityError = 0;
 511         scsiDev.dataPtr = 0;
 512         scsiDev.savedDataPtr = 0;
 513         scsiDev.dataLen = 0;
 514         scsiDev.status = GOOD;
 515         scsiDev.phase = SELECTION;
 516         scsiDev.lun = -1;
 517         scsiDev.discPriv = 0;
 518
 519         scsiDev.initiatorId = -1;
 520         scsiDev.target = NULL;
 521
 522         transfer.blocks = 0;
 523         transfer.currentBlock = 0;
 524
 525         scsiDev.postDataOutHook = NULL;
 526
 527         scsiDev.needSyncNegotiationAck = 0;
 528 }
 529
 530 static void process_SelectionPhase()
 531 {
 532         // Selection delays.
 533         // Many SCSI1 samplers that use a 5380 chip need a delay of at least 1ms.
 534         // The Mac Plus boot-time (ie. rom code) selection abort time
 535         // is < 1ms and must have no delay (standard suggests 250ms abort time)
 536         // Most newer SCSI2 hosts don't care either way.
 537         if (scsiDev.boardCfg.selectionDelay == 255) // auto
 538         {
 539                 if (scsiDev.compatMode < COMPAT_SCSI2)
 540                 {
 541                         s2s_delay_ms(1);
 542                 }
 543         }
 544         else if (scsiDev.boardCfg.selectionDelay != 0)
 545         {
 546                 s2s_delay_ms(scsiDev.boardCfg.selectionDelay);
 547         }
 548
 549         uint8_t selStatus = *SCSI_STS_SELECTED;
 550
 551         int tgtIndex;
 552         TargetState* target = NULL;
 553         for (tgtIndex = 0; tgtIndex < S2S_MAX_TARGETS; ++tgtIndex)
 554         {
 555                 if (scsiDev.targets[tgtIndex].targetId == (selStatus & 7))
 556                 {
 557                         target = &scsiDev.targets[tgtIndex];
 558                         break;
 559                 }
 560         }
 561         if ((target != NULL) && (selStatus & 0x40))
 562 // TODO         (goodParity || !(scsiDev.boardCfg.flags & S2S_CFG_ENABLE_PARITY) || !atnFlag)
 563         {
 564                 // We've been selected!
 565                 // Assert BSY - Selection success!
 566                 // must happen within 200us (Selection abort time) of seeing our
 567                 // ID + SEL.
 568                 // (Note: the initiator will be waiting the "Selection time-out delay"
 569                 // for our BSY response, which is actually a very generous 250ms)
 570                 *SCSI_CTRL_BSY = 1;
 571                 s2s_ledOn();
 572
 573                 scsiDev.target = target;
 574
 575                 // Do we enter MESSAGE OUT immediately ? SCSI 1 and 2 standards says
 576                 // move to MESSAGE OUT if ATN is true before we assert BSY.
 577                 // The initiator should assert ATN with SEL.
 578                 scsiDev.atnFlag = selStatus & 0x80;
 579
 580
 581                 // Unit attention breaks many older SCSI hosts. Disable it completely
 582                 // for SCSI-1 (and older) hosts, regardless of our configured setting.
 583                 // Enable the compatability mode also as many SASI and SCSI1
 584                 // controllers don't generate parity bits.
 585                 if (!scsiDev.atnFlag)
 586                 {
 587                         target->unitAttention = 0;
 588                         scsiDev.compatMode = COMPAT_SCSI1;
 589                 }
 590                 else if (!(scsiDev.boardCfg.flags & S2S_CFG_ENABLE_SCSI2))
 591                 {
 592                         scsiDev.compatMode = COMPAT_SCSI1;
 593                 }
 594                 else if (scsiDev.compatMode == COMPAT_UNKNOWN)
 595                 {
 596                         scsiDev.compatMode = COMPAT_SCSI2;
 597                 }
 598
 599                 scsiDev.selCount++;
 600
 601
 602                 // Save our initiator now that we're no longer in a time-critical
 603                 // section.
 604                 // SCSI1/SASI initiators may not set their own ID.
 605                 scsiDev.initiatorId = (selStatus >> 3) & 0x7;
 606
 607                 while (likely(!scsiDev.resetFlag) && scsiStatusSEL())
 608                 {
 609                         // Wait until the end of the selection phase.
 610                 }
 611
 612                 scsiDev.phase = COMMAND;
 613         }
 614         else if (!selStatus)
 615         {
 616                 scsiDev.phase = BUS_BUSY;
 617         }
 618 }
 619
 620 static void process_MessageOut()
 621 {
 622         scsiEnterPhase(MESSAGE_OUT);
 623
 624         scsiDev.atnFlag = 0;
 625         scsiDev.parityError = 0;
 626         scsiDev.msgOut = scsiReadByte();
 627         scsiDev.msgCount++;
 628
 629         if (scsiDev.parityError &&
 630                 (scsiDev.boardCfg.flags & S2S_CFG_ENABLE_PARITY) &&
 631                 (scsiDev.compatMode >= COMPAT_SCSI2))
 632         {
 633                 // Skip the remaining message bytes, and then start the MESSAGE_OUT
 634                 // phase again from the start. The initiator will re-send the
 635                 // same set of messages.
 636                 while (scsiStatusATN() && !scsiDev.resetFlag)
 637                 {
 638                         scsiReadByte();
 639                 }
 640
 641                 // Go-back and try the message again.
 642                 scsiDev.atnFlag = 1;
 643                 scsiDev.parityError = 0;
 644         }
 645         else if (scsiDev.msgOut == 0x00)
 646         {
 647                 // COMMAND COMPLETE. but why would the target be receiving this ? nfi.
 648                 enter_BusFree();
 649         }
 650         else if (scsiDev.msgOut == 0x06)
 651         {
 652                 // ABORT
 653                 scsiDiskReset();
 654                 enter_BusFree();
 655         }
 656         else if (scsiDev.msgOut == 0x0C)
 657         {
 658                 // BUS DEVICE RESET
 659
 660                 scsiDiskReset();
 661
 662                 scsiDev.target->unitAttention = SCSI_BUS_RESET;
 663
 664                 // ANY initiator can reset the reservation state via this message.
 665                 scsiDev.target->reservedId = -1;
 666                 scsiDev.target->reserverId = -1;
 667
 668                 // Cancel any sync negotiation
 669                 scsiDev.target->syncOffset = 0;
 670                 scsiDev.target->syncPeriod = 0;
 671
 672                 enter_BusFree();
 673         }
 674         else if (scsiDev.msgOut == 0x05)
 675         {
 676                 // Initiate Detected Error
 677                 // Ignore for now
 678         }
 679         else if (scsiDev.msgOut == 0x0F)
 680         {
 681                 // INITIATE RECOVERY
 682                 // Ignore for now
 683         }
 684         else if (scsiDev.msgOut == 0x10)
 685         {
 686                 // RELEASE RECOVERY
 687                 // Ignore for now
 688                 enter_BusFree();
 689         }
 690         else if (scsiDev.msgOut == MSG_REJECT)
 691         {
 692                 // Message Reject
 693                 // Oh well.
 694
 695                 if (scsiDev.needSyncNegotiationAck)
 696                 {
 697                         scsiDev.target->syncOffset = 0;
 698                         scsiDev.target->syncPeriod = 0;
 699                         scsiDev.needSyncNegotiationAck = 0;
 700                 }
 701         }
 702         else if (scsiDev.msgOut == 0x08)
 703         {
 704                 // NOP
 705         }
 706         else if (scsiDev.msgOut == 0x09)
 707         {
 708                 // Message Parity Error
 709                 // Go back and re-send the last message.
 710                 scsiDev.phase = MESSAGE_IN;
 711         }
 712         else if (scsiDev.msgOut & 0x80) // 0x80 -> 0xFF
 713         {
 714                 // IDENTIFY
 715                 if ((scsiDev.msgOut & 0x18) || // Reserved bits set.
 716                         (scsiDev.msgOut & 0x20))  // We don't have any target routines!
 717                 {
 718                         messageReject();
 719                 }
 720
 721                 scsiDev.lun = scsiDev.msgOut & 0x7;
 722                 scsiDev.discPriv =
 723                         ((scsiDev.msgOut & 0x40) && (scsiDev.initiatorId >= 0))
 724                                 ? 1 : 0;
 725         }
 726         else if (scsiDev.msgOut >= 0x20 && scsiDev.msgOut <= 0x2F)
 727         {
 728                 // Two byte message. We don't support these. read and discard.
 729                 scsiReadByte();
 730
 731                 if (scsiDev.msgOut == 0x23) {
 732                         // Ignore Wide Residue. We're only 8 bit anyway.
 733                 } else {
 734                         messageReject();
 735                 }
 736         }
 737         else if (scsiDev.msgOut == 0x01)
 738         {
 739                 int i;
 740
 741                 // Extended message.
 742                 int msgLen = scsiReadByte();
 743                 if (msgLen == 0) msgLen = 256;
 744                 uint8_t extmsg[256];
 745                 for (i = 0; i < msgLen && !scsiDev.resetFlag; ++i)
 746                 {
 747                         // Discard bytes.
 748                         extmsg[i] = scsiReadByte();
 749                 }
 750
 751                 if (extmsg[0] == 3 && msgLen == 2) // Wide Data Request
 752                 {
 753                         // Negotiate down to 8bit
 754                         scsiEnterPhase(MESSAGE_IN);
 755                         static const uint8_t WDTR[] = {0x01, 0x02, 0x03, 0x00};
 756                         scsiWrite(WDTR, sizeof(WDTR));
 757                 }
 758                 else if (extmsg[0] == 1 && msgLen == 3) // Synchronous data request
 759                 {
 760                         int transferPeriod = extmsg[3];
 761                         int offset = extmsg[4];
 762
 763                         if (transferPeriod > 50) // 200ns, 5MB/s
 764                         {
 765                                 scsiDev.target->syncOffset = 0;
 766                                 scsiDev.target->syncPeriod = 0;
 767                         } else {
 768                                 scsiDev.target->syncOffset = offset < 15 ? offset : 15;
 769                                 if (transferPeriod <= 25)
 770                                 {
 771                                         scsiDev.target->syncPeriod = 25; // 10MB/s
 772                                 } else {
 773                                         scsiDev.target->syncPeriod = 50; // 5MB/s
 774                                 }
 775                         }
 776
 777                         scsiEnterPhase(MESSAGE_IN);
 778                         uint8_t SDTR[] = {0x01, 0x03, 0x01, scsiDev.target->syncPeriod, scsiDev.target->syncOffset};
 779                         scsiWrite(SDTR, sizeof(SDTR));
 780                         scsiDev.needSyncNegotiationAck = 1; // Check if this message is rejected.
 781                 }
 782                 else
 783                 {
 784                         // Not supported
 785                         messageReject();
 786                 }
 787         }
 788         else
 789         {
 790                 messageReject();
 791         }
 792
 793         // Re-check the ATN flag in case it stays asserted.
 794         scsiDev.atnFlag |= scsiStatusATN();
 795
 796         if (!scsiDev.atnFlag)
 797         {
 798                 // Message wasn't rejected!
 799                 scsiDev.needSyncNegotiationAck = 0;
 800         }
 801 }
 802
 803 void scsiPoll(void)
 804 {
 805         if (unlikely(scsiDev.resetFlag))
 806         {
 807                 scsiReset();
 808                 if ((scsiDev.resetFlag = scsiStatusRST()))
 809                 {
 810                         // Still in reset phase. Do not try and process any commands.
 811                         return;
 812                 }
 813         }
 814
 815         switch (scsiDev.phase)
 816         {
 817         case BUS_FREE:
 818                 if (scsiStatusBSY())
 819                 {
 820                         scsiDev.phase = BUS_BUSY;
 821                 }
 822                 // The Arbitration phase is optional for SCSI1/SASI hosts if there is only
 823                 // one initiator in the chain. Support this by moving
 824                 // straight to selection if SEL is asserted.
 825                 // ie. the initiator won't assert BSY and it's own ID before moving to selection.
 826                 else if (*SCSI_STS_SELECTED)
 827                 {
 828                         enter_SelectionPhase();
 829                 }
 830         break;
 831
 832         case BUS_BUSY:
 833                 // Someone is using the bus. Perhaps they are trying to
 834                 // select us.
 835                 if (*SCSI_STS_SELECTED)
 836                 {
 837                         enter_SelectionPhase();
 838                 }
 839                 else if (!scsiStatusBSY())
 840                 {
 841                         scsiDev.phase = BUS_FREE;
 842                 }
 843         break;
 844
 845         case ARBITRATION:
 846                 // TODO Support reselection.
 847                 break;
 848
 849         case SELECTION:
 850                 process_SelectionPhase();
 851         break;
 852
 853         case RESELECTION:
 854                 // Not currently supported!
 855         break;
 856
 857         case COMMAND:
 858                 // Do not check ATN here. SCSI 1 & 2 initiators must set ATN
 859                 // and SEL together upon entering the selection phase if they
 860                 // want to send a message (IDENTIFY) immediately.
 861                 if (scsiDev.atnFlag)
 862                 {
 863                         process_MessageOut();
 864                 }
 865                 else
 866                 {
 867                         process_Command();
 868                 }
 869         break;
 870
 871         case DATA_IN:
 872                 scsiDev.atnFlag |= scsiStatusATN();
 873                 if (scsiDev.atnFlag)
 874                 {
 875                         process_MessageOut();
 876                 }
 877                 else
 878                 {
 879                         process_DataIn();
 880                 }
 881         break;
 882
 883         case DATA_OUT:
 884                 scsiDev.atnFlag |= scsiStatusATN();
 885                 if (scsiDev.atnFlag)
 886                 {
 887                         process_MessageOut();
 888                 }
 889                 else
 890                 {
 891                         process_DataOut();
 892                 }
 893         break;
 894
 895         case STATUS:
 896                 scsiDev.atnFlag |= scsiStatusATN();
 897                 if (scsiDev.atnFlag)
 898                 {
 899                         process_MessageOut();
 900                 }
 901                 else
 902                 {
 903                         process_Status();
 904                 }
 905         break;
 906
 907         case MESSAGE_IN:
 908                 scsiDev.atnFlag |= scsiStatusATN();
 909                 if (scsiDev.atnFlag)
 910                 {
 911                         process_MessageOut();
 912                 }
 913                 else
 914                 {
 915                         process_MessageIn();
 916                 }
 917
 918         break;
 919
 920         case MESSAGE_OUT:
 921                 process_MessageOut();
 922         break;
 923         }
 924 }
 925
 926 void scsiInit()
 927 {
 928         static int firstInit = 1;
 929
 930         scsiDev.atnFlag = 0;
 931         scsiDev.resetFlag = 1;
 932         scsiDev.phase = BUS_FREE;
 933         scsiDev.target = NULL;
 934         scsiDev.compatMode = COMPAT_UNKNOWN;
 935
 936         int i;
 937         for (i = 0; i < S2S_MAX_TARGETS; ++i)
 938         {
 939                 const S2S_TargetCfg* cfg = s2s_getConfigByIndex(i);
 940                 if (cfg && (cfg->scsiId & S2S_CFG_TARGET_ENABLED))
 941                 {
 942                         scsiDev.targets[i].targetId = cfg->scsiId & S2S_CFG_TARGET_ID_BITS;
 943                         scsiDev.targets[i].cfg = cfg;
 944
 945                         scsiDev.targets[i].liveCfg.bytesPerSector = cfg->bytesPerSector;
 946                 }
 947                 else
 948                 {
 949                         scsiDev.targets[i].targetId = 0xff;
 950                         scsiDev.targets[i].cfg = NULL;
 951                 }
 952                 scsiDev.targets[i].reservedId = -1;
 953                 scsiDev.targets[i].reserverId = -1;
 954                 if (firstInit)
 955                 {
 956                         scsiDev.targets[i].unitAttention = POWER_ON_RESET;
 957                 }
 958                 else
 959                 {
 960                         scsiDev.targets[i].unitAttention = PARAMETERS_CHANGED;
 961                 }
 962                 scsiDev.targets[i].sense.code = NO_SENSE;
 963                 scsiDev.targets[i].sense.asc = NO_ADDITIONAL_SENSE_INFORMATION;
 964
 965                 scsiDev.targets[i].syncOffset = 0;
 966                 scsiDev.targets[i].syncPeriod = 0;
 967         }
 968         firstInit = 0;
 969 }
 970
 971 /* TODO REENABLE
 972 void scsiDisconnect()
 973 {
 974         scsiEnterPhase(MESSAGE_IN);
 975         scsiWriteByte(0x02); // save data pointer
 976         scsiWriteByte(0x04); // disconnect msg.
 977
 978         // For now, the caller is responsible for tracking the disconnected
 979         // state, and calling scsiReconnect.
 980         // Ideally the client would exit their loop and we'd implement this
 981         // as part of scsiPoll
 982         int phase = scsiDev.phase;
 983         enter_BusFree();
 984         scsiDev.phase = phase;
 985 }
 986 */
 987
 988 /* TODO REENABLE
 989 int scsiReconnect()
 990 {
 991         int reconnected = 0;
 992
 993         int sel = SCSI_ReadFilt(SCSI_Filt_SEL);
 994         int bsy = SCSI_ReadFilt(SCSI_Filt_BSY);
 995         if (!sel && !bsy)
 996         {
 997                 s2s_delay_us(1);
 998                 sel = SCSI_ReadFilt(SCSI_Filt_SEL);
 999                 bsy = SCSI_ReadFilt(SCSI_Filt_BSY);
1000         }
1001
1002         if (!sel && !bsy)
1003         {
1004                 // Arbitrate.
1005                 s2s_ledOn();
1006                 uint8_t scsiIdMask = 1 << scsiDev.target->targetId;
1007                 SCSI_Out_Bits_Write(scsiIdMask);
1008                 SCSI_Out_Ctl_Write(1); // Write bits manually.
1009                 SCSI_SetPin(SCSI_Out_BSY);
1010
1011                 s2s_delay_us(3); // arbitrate delay. 2.4us.
1012
1013                 uint8_t dbx = scsiReadDBxPins();
1014                 sel = SCSI_ReadFilt(SCSI_Filt_SEL);
1015                 if (sel || ((dbx ^ scsiIdMask) > scsiIdMask))
1016                 {
1017                         // Lost arbitration.
1018                         SCSI_Out_Ctl_Write(0);
1019                         SCSI_ClearPin(SCSI_Out_BSY);
1020                         s2s_ledOff();
1021                 }
1022                 else
1023                 {
1024                         // Won arbitration
1025                         SCSI_SetPin(SCSI_Out_SEL);
1026                         s2s_delay_us(1); // Bus clear + Bus settle.
1027
1028                         // Reselection phase
1029                         SCSI_CTL_PHASE_Write(__scsiphase_io);
1030                         SCSI_Out_Bits_Write(scsiIdMask | (1 << scsiDev.initiatorId));
1031                         scsiDeskewDelay(); // 2 deskew delays
1032                         scsiDeskewDelay(); // 2 deskew delays
1033                         SCSI_ClearPin(SCSI_Out_BSY);
1034                         s2s_delay_us(1);  // Bus Settle Delay
1035
1036                         uint32_t waitStart_ms = getTime_ms();
1037                         bsy = SCSI_ReadFilt(SCSI_Filt_BSY);
1038                         // Wait for initiator.
1039                         while (
1040                                 !bsy &&
1041                                 !scsiDev.resetFlag &&
1042                                 (elapsedTime_ms(waitStart_ms) < 250))
1043                         {
1044                                 bsy = SCSI_ReadFilt(SCSI_Filt_BSY);
1045                         }
1046
1047                         if (bsy)
1048                         {
1049                                 SCSI_SetPin(SCSI_Out_BSY);
1050                                 scsiDeskewDelay(); // 2 deskew delays
1051                                 scsiDeskewDelay(); // 2 deskew delays
1052                                 SCSI_ClearPin(SCSI_Out_SEL);
1053
1054                                 // Prepare for the initial IDENTIFY message.
1055                                 SCSI_Out_Ctl_Write(0);
1056                                 scsiEnterPhase(MESSAGE_IN);
1057
1058                                 // Send identify command
1059                                 scsiWriteByte(0x80);
1060
1061                                 scsiEnterPhase(scsiDev.phase);
1062                                 reconnected = 1;
1063                         }
1064                         else
1065                         {
1066                                 // reselect timeout.
1067                                 SCSI_Out_Ctl_Write(0);
1068                                 SCSI_ClearPin(SCSI_Out_SEL);
1069                                 SCSI_CTL_PHASE_Write(0);
1070                                 s2s_ledOff();
1071                         }
1072                 }
1073         }
1074         return reconnected;
1075 }
1076 */
1077