software/SCSI2SD/src/scsi.c

   1 //      Copyright (C) 2014 Michael McMaster <michael@codesrc.com>\r
   2 //\r
   3 //      This file is part of SCSI2SD.\r
   4 //\r
   5 //      SCSI2SD is free software: you can redistribute it and/or modify\r
   6 //      it under the terms of the GNU General Public License as published by\r
   7 //      the Free Software Foundation, either version 3 of the License, or\r
   8 //      (at your option) any later version.\r
   9 //\r
  10 //      SCSI2SD is distributed in the hope that it will be useful,\r
  11 //      but WITHOUT ANY WARRANTY; without even the implied warranty of\r
  12 //      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\r
  13 //      GNU General Public License for more details.\r
  14 //\r
  15 //      You should have received a copy of the GNU General Public License\r
  16 //      along with SCSI2SD.  If not, see <http://www.gnu.org/licenses/>.\r
  17 \r
  18 #include "device.h"\r
  19 #include "scsi.h"\r
  20 #include "scsiPhy.h"\r
  21 #include "config.h"\r
  22 #include "bits.h"\r
  23 #include "diagnostic.h"\r
  24 #include "disk.h"\r
  25 #include "inquiry.h"\r
  26 #include "led.h"\r
  27 #include "mode.h"\r
  28 #include "disk.h"\r
  29 \r
  30 #include <string.h>\r
  31 \r
  32 // Global SCSI device state.\r
  33 ScsiDevice scsiDev;\r
  34 \r
  35 static void enter_SelectionPhase(void);\r
  36 static void process_SelectionPhase(void);\r
  37 static void enter_BusFree(void);\r
  38 static void enter_MessageIn(uint8 message);\r
  39 static void process_MessageIn(void);\r
  40 static void enter_Status(uint8 status);\r
  41 static void process_Status(void);\r
  42 static void enter_DataIn(int len);\r
  43 static void process_DataIn(void);\r
  44 static void process_DataOut(void);\r
  45 static void process_Command(void);\r
  46 \r
  47 static void doReserveRelease(void);\r
  48 \r
  49 static void enter_BusFree()\r
  50 {\r
  51         // This delay probably isn't needed for most SCSI hosts, but it won't\r
  52         // hurt either. It's possible some of the samplers needed this delay.\r
  53         CyDelayUs(2);\r
  54 \r
  55         SCSI_ClearPin(SCSI_Out_BSY);\r
  56         // We now have a Bus Clear Delay of 800ns to release remaining signals.\r
  57         SCSI_CTL_PHASE_Write(0);\r
  58 \r
  59         // Wait for the initiator to cease driving signals\r
  60         // Bus settle delay + bus clear delay = 1200ns\r
  61         CyDelayUs(2);\r
  62 \r
  63         ledOff();\r
  64         scsiDev.phase = BUS_FREE;\r
  65 }\r
  66 \r
  67 static void enter_MessageIn(uint8 message)\r
  68 {\r
  69         scsiDev.msgIn = message;\r
  70         scsiDev.phase = MESSAGE_IN;\r
  71 }\r
  72 \r
  73 static void process_MessageIn()\r
  74 {\r
  75         scsiEnterPhase(MESSAGE_IN);\r
  76         scsiWriteByte(scsiDev.msgIn);\r
  77 \r
  78         if (scsiDev.atnFlag)\r
  79         {\r
  80                 // If there was a parity error, we go\r
  81                 // back to MESSAGE_OUT first, get out parity error message, then come\r
  82                 // back here.\r
  83         }\r
  84         else if ((scsiDev.msgIn == MSG_LINKED_COMMAND_COMPLETE) ||\r
  85                 (scsiDev.msgIn == MSG_LINKED_COMMAND_COMPLETE_WITH_FLAG))\r
  86         {\r
  87                 // Go back to the command phase and start again.\r
  88                 scsiDev.phase = COMMAND;\r
  89                 scsiDev.parityError = 0;\r
  90                 scsiDev.dataPtr = 0;\r
  91                 scsiDev.savedDataPtr = 0;\r
  92                 scsiDev.dataLen = 0;\r
  93                 scsiDev.status = GOOD;\r
  94                 transfer.blocks = 0;\r
  95                 transfer.currentBlock = 0;\r
  96         }\r
  97         else /*if (scsiDev.msgIn == MSG_COMMAND_COMPLETE)*/\r
  98         {\r
  99                 enter_BusFree();\r
 100         }\r
 101 }\r
 102 \r
 103 static void messageReject()\r
 104 {\r
 105         scsiEnterPhase(MESSAGE_IN);\r
 106         scsiWriteByte(MSG_REJECT);\r
 107 }\r
 108 \r
 109 static void enter_Status(uint8 status)\r
 110 {\r
 111         scsiDev.status = status;\r
 112         scsiDev.phase = STATUS;\r
 113 \r
 114 \r
 115         #ifdef MM_DEBUG\r
 116         scsiDev.lastStatus = scsiDev.status;\r
 117         scsiDev.lastSense = scsiDev.sense.code;\r
 118         #endif\r
 119 }\r
 120 \r
 121 static void process_Status()\r
 122 {\r
 123         scsiEnterPhase(STATUS);\r
 124 \r
 125         uint8 message;\r
 126 \r
 127         uint8 control = scsiDev.cdb[scsiDev.cdbLen - 1];\r
 128         if ((scsiDev.status == GOOD) && (control & 0x01))\r
 129         {\r
 130                 // Linked command.\r
 131                 scsiDev.status = INTERMEDIATE;\r
 132                 if (control & 0x02)\r
 133                 {\r
 134                         message = MSG_LINKED_COMMAND_COMPLETE_WITH_FLAG;\r
 135                 }\r
 136                 else\r
 137                 {\r
 138                         message = MSG_LINKED_COMMAND_COMPLETE;\r
 139                 }\r
 140         }\r
 141         else\r
 142         {\r
 143                 message = MSG_COMMAND_COMPLETE;\r
 144         }\r
 145         scsiWriteByte(scsiDev.status);\r
 146 \r
 147         #ifdef MM_DEBUG\r
 148         scsiDev.lastStatus = scsiDev.status;\r
 149         scsiDev.lastSense = scsiDev.sense.code;\r
 150         #endif\r
 151 \r
 152         // Command Complete occurs AFTER a valid status has been\r
 153         // sent. then we go bus-free.\r
 154         enter_MessageIn(message);\r
 155 }\r
 156 \r
 157 static void enter_DataIn(int len)\r
 158 {\r
 159         scsiDev.dataLen = len;\r
 160         scsiDev.phase = DATA_IN;\r
 161 }\r
 162 \r
 163 static void process_DataIn()\r
 164 {\r
 165         uint32 len;\r
 166 \r
 167         if (scsiDev.dataLen > sizeof(scsiDev.data))\r
 168         {\r
 169                 scsiDev.dataLen = sizeof(scsiDev.data);\r
 170         }\r
 171 \r
 172         len = scsiDev.dataLen - scsiDev.dataPtr;\r
 173         if (len > 0)\r
 174         {\r
 175                 scsiEnterPhase(DATA_IN);\r
 176                 scsiWrite(scsiDev.data + scsiDev.dataPtr, len);\r
 177                 scsiDev.dataPtr += len;\r
 178         }\r
 179 \r
 180         if ((scsiDev.dataPtr >= scsiDev.dataLen) &&\r
 181                 (transfer.currentBlock == transfer.blocks))\r
 182         {\r
 183                 enter_Status(GOOD);\r
 184         }\r
 185 }\r
 186 \r
 187 static void process_DataOut()\r
 188 {\r
 189         uint32 len;\r
 190 \r
 191         if (scsiDev.dataLen > sizeof(scsiDev.data))\r
 192         {\r
 193                 scsiDev.dataLen = sizeof(scsiDev.data);\r
 194         }\r
 195 \r
 196         scsiDev.parityError = 0;\r
 197         len = scsiDev.dataLen - scsiDev.dataPtr;\r
 198         if (len > 0)\r
 199         {\r
 200                 scsiEnterPhase(DATA_OUT);\r
 201 \r
 202                 scsiRead(scsiDev.data + scsiDev.dataPtr, len);\r
 203                 scsiDev.dataPtr += len;\r
 204 \r
 205                 // TODO re-implement parity checking\r
 206                 if (0 && scsiDev.parityError && config->enableParity)\r
 207                 {\r
 208                         scsiDev.sense.code = ABORTED_COMMAND;\r
 209                         scsiDev.sense.asc = SCSI_PARITY_ERROR;\r
 210                         enter_Status(CHECK_CONDITION);\r
 211                 }\r
 212         }\r
 213 \r
 214         if ((scsiDev.dataPtr >= scsiDev.dataLen) &&\r
 215                 (transfer.currentBlock == transfer.blocks))\r
 216         {\r
 217                 if (scsiDev.postDataOutHook != NULL)\r
 218                 {\r
 219                         scsiDev.postDataOutHook();\r
 220                 }\r
 221                 else\r
 222                 {\r
 223                         enter_Status(GOOD);\r
 224                 }\r
 225         }\r
 226 }\r
 227 \r
 228 static const uint8 CmdGroupBytes[8] = {6, 10, 10, 6, 6, 12, 6, 6};\r
 229 static void process_Command()\r
 230 {\r
 231         int group;\r
 232         uint8 command;\r
 233         uint8 lun;\r
 234         uint8 control;\r
 235 \r
 236         scsiEnterPhase(COMMAND);\r
 237         scsiDev.parityError = 0;\r
 238 \r
 239         memset(scsiDev.cdb, 0, sizeof(scsiDev.cdb));\r
 240         scsiDev.cdb[0] = scsiReadByte();\r
 241 \r
 242         group = scsiDev.cdb[0] >> 5;\r
 243         scsiDev.cdbLen = CmdGroupBytes[group];\r
 244         scsiRead(scsiDev.cdb + 1, scsiDev.cdbLen - 1);\r
 245 \r
 246         command = scsiDev.cdb[0];\r
 247         lun = scsiDev.cdb[1] >> 5;\r
 248         control = scsiDev.cdb[scsiDev.cdbLen - 1];\r
 249 \r
 250         #ifdef MM_DEBUG\r
 251         scsiDev.cmdCount++;\r
 252         #endif\r
 253 \r
 254         if (scsiDev.resetFlag)\r
 255         {\r
 256 #ifdef MM_DEBUG\r
 257                 // Don't log bogus commands\r
 258                 scsiDev.cmdCount--;\r
 259                 memset(scsiDev.cdb, 0xff, sizeof(scsiDev.cdb));\r
 260 #endif\r
 261                 return;\r
 262         }\r
 263         else if (scsiDev.parityError)\r
 264         {\r
 265                 scsiDev.sense.code = ABORTED_COMMAND;\r
 266                 scsiDev.sense.asc = SCSI_PARITY_ERROR;\r
 267                 enter_Status(CHECK_CONDITION);\r
 268         }\r
 269         else if ((control & 0x02) && ((control & 0x01) == 0))\r
 270         {\r
 271                 // FLAG set without LINK flag.\r
 272                 scsiDev.sense.code = ILLEGAL_REQUEST;\r
 273                 scsiDev.sense.asc = INVALID_FIELD_IN_CDB;\r
 274                 enter_Status(CHECK_CONDITION);\r
 275         }\r
 276         else if (command == 0x12)\r
 277         {\r
 278                 scsiInquiry();\r
 279         }\r
 280         else if (command == 0x03)\r
 281         {\r
 282                 // REQUEST SENSE\r
 283                 uint32 allocLength = scsiDev.cdb[4];\r
 284                 if (allocLength == 0) allocLength = 256;\r
 285                 memset(scsiDev.data, 0, 18);\r
 286                 scsiDev.data[0] = 0xF0;\r
 287                 scsiDev.data[2] = scsiDev.sense.code & 0x0F;\r
 288 \r
 289                 scsiDev.data[3] = transfer.lba >> 24;\r
 290                 scsiDev.data[4] = transfer.lba >> 16;\r
 291                 scsiDev.data[5] = transfer.lba >> 8;\r
 292                 scsiDev.data[6] = transfer.lba;\r
 293 \r
 294                 // Additional bytes if there are errors to report\r
 295                 int responseLength;\r
 296                 if (scsiDev.sense.code == NO_SENSE)\r
 297                 {\r
 298                         responseLength = 8;\r
 299                 }\r
 300                 else\r
 301                 {\r
 302                         responseLength = 18;\r
 303                         scsiDev.data[7] = 10; // additional length\r
 304                         scsiDev.data[12] = scsiDev.sense.asc >> 8;\r
 305                         scsiDev.data[13] = scsiDev.sense.asc;\r
 306                 }\r
 307 \r
 308                 // Silently truncate results. SCSI-2 spec 8.2.14.\r
 309                 enter_DataIn(\r
 310                         (allocLength < responseLength) ? allocLength : responseLength\r
 311                         );\r
 312 \r
 313                 // This is a good time to clear out old sense information.\r
 314                 scsiDev.sense.code = NO_SENSE;\r
 315                 scsiDev.sense.asc = NO_ADDITIONAL_SENSE_INFORMATION;\r
 316         }\r
 317         // Some old SCSI drivers do NOT properly support\r
 318         // unitAttention. eg. the Mac Plus would trigger a SCSI reset\r
 319         // on receiving the unit attention response on boot, thus\r
 320         // triggering another unit attention condition.\r
 321         else if (scsiDev.unitAttention && config->enableUnitAttention)\r
 322         {\r
 323                 scsiDev.sense.code = UNIT_ATTENTION;\r
 324                 scsiDev.sense.asc = scsiDev.unitAttention;\r
 325 \r
 326                 // If initiator doesn't do REQUEST SENSE for the next command, then\r
 327                 // data is lost.\r
 328                 scsiDev.unitAttention = 0;\r
 329 \r
 330                 enter_Status(CHECK_CONDITION);\r
 331         }\r
 332         else if (lun)\r
 333         {\r
 334                 scsiDev.sense.code = ILLEGAL_REQUEST;\r
 335                 scsiDev.sense.asc = LOGICAL_UNIT_NOT_SUPPORTED;\r
 336                 enter_Status(CHECK_CONDITION);\r
 337         }\r
 338         else if (command == 0x17 || command == 0x16)\r
 339         {\r
 340                 doReserveRelease();\r
 341         }\r
 342         else if ((scsiDev.reservedId >= 0) &&\r
 343                 (scsiDev.reservedId != scsiDev.initiatorId))\r
 344         {\r
 345                 enter_Status(CONFLICT);\r
 346         }\r
 347         else if (command == 0x1C)\r
 348         {\r
 349                 scsiReceiveDiagnostic();\r
 350         }\r
 351         else if (command == 0x1D)\r
 352         {\r
 353                 scsiSendDiagnostic();\r
 354         }\r
 355         else if (\r
 356                 !scsiModeCommand() &&\r
 357                 !scsiDiskCommand())\r
 358         {\r
 359                 scsiDev.sense.code = ILLEGAL_REQUEST;\r
 360                 scsiDev.sense.asc = INVALID_COMMAND_OPERATION_CODE;\r
 361                 enter_Status(CHECK_CONDITION);\r
 362         }\r
 363 \r
 364         // Successful\r
 365         if (scsiDev.phase == COMMAND) // No status set, and not in DATA_IN\r
 366         {\r
 367                 enter_Status(GOOD);\r
 368         }\r
 369 \r
 370 }\r
 371 \r
 372 static void doReserveRelease()\r
 373 {\r
 374         int extentReservation = scsiDev.cdb[1] & 1;\r
 375         int thirdPty = scsiDev.cdb[1] & 0x10;\r
 376         int thirdPtyId = (scsiDev.cdb[1] >> 1) & 0x7;\r
 377         uint8 command = scsiDev.cdb[0];\r
 378 \r
 379         int canRelease =\r
 380                 (!thirdPty && (scsiDev.initiatorId == scsiDev.reservedId)) ||\r
 381                         (thirdPty &&\r
 382                                 (scsiDev.reserverId == scsiDev.initiatorId) &&\r
 383                                 (scsiDev.reservedId == thirdPtyId)\r
 384                         );\r
 385 \r
 386         if (extentReservation)\r
 387         {\r
 388                 // Not supported.\r
 389                 scsiDev.sense.code = ILLEGAL_REQUEST;\r
 390                 scsiDev.sense.asc = INVALID_FIELD_IN_CDB;\r
 391                 enter_Status(CHECK_CONDITION);\r
 392         }\r
 393         else if (command == 0x17) // release\r
 394         {\r
 395                 if ((scsiDev.reservedId < 0) || canRelease)\r
 396                 {\r
 397                         scsiDev.reservedId = -1;\r
 398                         scsiDev.reserverId = -1;\r
 399                 }\r
 400                 else\r
 401                 {\r
 402                         enter_Status(CONFLICT);\r
 403                 }\r
 404         }\r
 405         else // assume reserve.\r
 406         {\r
 407                 if ((scsiDev.reservedId < 0) || canRelease)\r
 408                 {\r
 409                         scsiDev.reserverId = scsiDev.initiatorId;\r
 410                         if (thirdPty)\r
 411                         {\r
 412                                 scsiDev.reservedId = thirdPtyId;\r
 413                         }\r
 414                         else\r
 415                         {\r
 416                                 scsiDev.reservedId = scsiDev.initiatorId;\r
 417                         }\r
 418                 }\r
 419                 else\r
 420                 {\r
 421                         // Already reserved by someone else!\r
 422                         enter_Status(CONFLICT);\r
 423                 }\r
 424         }\r
 425 }\r
 426 \r
 427 static void scsiReset()\r
 428 {\r
 429 #ifdef MM_DEBUG\r
 430         scsiDev.rstCount++;\r
 431 #endif\r
 432         ledOff();\r
 433 \r
 434         scsiPhyReset();\r
 435 \r
 436         scsiDev.parityError = 0;\r
 437         scsiDev.phase = BUS_FREE;\r
 438         scsiDev.atnFlag = 0;\r
 439         scsiDev.resetFlag = 0;\r
 440 \r
 441         if (scsiDev.unitAttention != POWER_ON_RESET)\r
 442         {\r
 443                 scsiDev.unitAttention = SCSI_BUS_RESET;\r
 444         }\r
 445         scsiDev.reservedId = -1;\r
 446         scsiDev.reserverId = -1;\r
 447         scsiDev.sense.code = NO_SENSE;\r
 448         scsiDev.sense.asc = NO_ADDITIONAL_SENSE_INFORMATION;\r
 449         scsiDiskReset();\r
 450 \r
 451         scsiDev.postDataOutHook = NULL;\r
 452 \r
 453         // Sleep to allow the bus to settle down a bit.\r
 454         // We must be ready again within the "Reset to selection time" of\r
 455         // 250ms.\r
 456         // There is no guarantee that the RST line will be negated by then.\r
 457         // NOTE: We could be connected and powered by USB for configuration,\r
 458         // in which case TERMPWR cannot be supplied, and reset will ALWAYS\r
 459         // be true.\r
 460         CyDelay(10); // 10ms.\r
 461 }\r
 462 \r
 463 static void enter_SelectionPhase()\r
 464 {\r
 465         // Ignore stale versions of this flag, but ensure we know the\r
 466         // current value if the flag is still set.\r
 467         scsiDev.atnFlag = 0;\r
 468         scsiDev.parityError = 0;\r
 469         scsiDev.dataPtr = 0;\r
 470         scsiDev.savedDataPtr = 0;\r
 471         scsiDev.dataLen = 0;\r
 472         scsiDev.status = GOOD;\r
 473         scsiDev.phase = SELECTION;\r
 474 \r
 475         transfer.blocks = 0;\r
 476         transfer.currentBlock = 0;\r
 477 \r
 478         scsiDev.postDataOutHook = NULL;\r
 479 }\r
 480 \r
 481 static void process_SelectionPhase()\r
 482 {\r
 483         int sel = SCSI_ReadPin(SCSI_In_SEL);\r
 484         int bsy = SCSI_ReadPin(SCSI_In_BSY);\r
 485 \r
 486         // Only read these pins AFTER SEL and BSY - we don't want to catch them\r
 487         // during a transition period.\r
 488         uint8 mask = scsiReadDBxPins();\r
 489         int maskBitCount = countBits(mask);\r
 490         int goodParity = (Lookup_OddParity[mask] == SCSI_ReadPin(SCSI_In_DBP));\r
 491 \r
 492         if (!bsy && sel &&\r
 493                 (mask & scsiDev.scsiIdMask) &&\r
 494                 (goodParity || !config->enableParity) && (maskBitCount <= 2))\r
 495         {\r
 496                 // Do we enter MESSAGE OUT immediately ? SCSI 1 and 2 standards says\r
 497                 // move to MESSAGE OUT if ATN is true before we assert BSY.\r
 498                 // The initiator should assert ATN with SEL.\r
 499                 scsiDev.atnFlag = SCSI_ReadPin(SCSI_ATN_INT);\r
 500                 \r
 501                 // Unit attention breaks many older SCSI hosts. Disable it completely for\r
 502                 // SCSI-1 (and older) hosts, regardless of our configured setting.\r
 503                 if (!scsiDev.atnFlag)\r
 504                 {\r
 505                         scsiDev.unitAttention = 0;\r
 506                 }\r
 507 \r
 508                 // We've been selected!\r
 509                 // Assert BSY - Selection success!\r
 510                 // must happen within 200us (Selection abort time) of seeing our\r
 511                 // ID + SEL.\r
 512                 // (Note: the initiator will be waiting the "Selection time-out delay"\r
 513                 // for our BSY response, which is actually a very generous 250ms)\r
 514                 SCSI_SetPin(SCSI_Out_BSY);\r
 515                 ledOn();\r
 516 \r
 517                 #ifdef MM_DEBUG\r
 518                 scsiDev.selCount++;\r
 519                 #endif\r
 520 \r
 521                 // Wait until the end of the selection phase.\r
 522                 while (!scsiDev.resetFlag)\r
 523                 {\r
 524                         if (!SCSI_ReadPin(SCSI_In_SEL))\r
 525                         {\r
 526                                 break;\r
 527                         }\r
 528                 }\r
 529 \r
 530                 // Save our initiator now that we're no longer in a time-critical\r
 531                 // section.\r
 532                 // SCSI1/SASI initiators may not set their own ID.\r
 533                 if (maskBitCount == 2)\r
 534                 {\r
 535                         int i;\r
 536                         uint8 initiatorMask = mask ^ scsiDev.scsiIdMask;\r
 537                         scsiDev.initiatorId = 0;\r
 538                         for (i = 0; i < 8; ++i)\r
 539                         {\r
 540                                 if (initiatorMask & (1 << i))\r
 541                                 {\r
 542                                         scsiDev.initiatorId = i;\r
 543                                         break;\r
 544                                 }\r
 545                         }\r
 546                 }\r
 547                 else\r
 548                 {\r
 549                         scsiDev.initiatorId = -1;\r
 550                 }\r
 551 \r
 552                 scsiDev.phase = COMMAND;\r
 553         }\r
 554         else if (!sel)\r
 555         {\r
 556                 scsiDev.phase = BUS_BUSY;\r
 557         }\r
 558 }\r
 559 \r
 560 static void process_MessageOut()\r
 561 {\r
 562         scsiEnterPhase(MESSAGE_OUT);\r
 563 \r
 564         scsiDev.atnFlag = 0;\r
 565         scsiDev.parityError = 0;\r
 566         scsiDev.msgOut = scsiReadByte();\r
 567 #ifdef MM_DEBUG\r
 568         scsiDev.msgCount++;\r
 569 #endif\r
 570 \r
 571         if (scsiDev.parityError)\r
 572         {\r
 573                 // Skip the remaining message bytes, and then start the MESSAGE_OUT\r
 574                 // phase again from the start. The initiator will re-send the\r
 575                 // same set of messages.\r
 576                 while (SCSI_ReadPin(SCSI_ATN_INT) && !scsiDev.resetFlag)\r
 577                 {\r
 578                         scsiReadByte();\r
 579                 }\r
 580 \r
 581                 // Go-back and try the message again.\r
 582                 scsiDev.atnFlag = 1;\r
 583                 scsiDev.parityError = 0;\r
 584         }\r
 585         else if (scsiDev.msgOut == 0x00)\r
 586         {\r
 587                 // COMMAND COMPLETE. but why would the target be receiving this ? nfi.\r
 588                 enter_BusFree();\r
 589         }\r
 590         else if (scsiDev.msgOut == 0x06)\r
 591         {\r
 592                 // ABORT\r
 593                 scsiDiskReset();\r
 594                 enter_BusFree();\r
 595         }\r
 596         else if (scsiDev.msgOut == 0x0C)\r
 597         {\r
 598                 // BUS DEVICE RESET\r
 599 \r
 600                 scsiDiskReset();\r
 601 \r
 602                 scsiDev.unitAttention = SCSI_BUS_RESET;\r
 603 \r
 604                 // ANY initiator can reset the reservation state via this message.\r
 605                 scsiDev.reservedId = -1;\r
 606                 scsiDev.reserverId = -1;\r
 607                 enter_BusFree();\r
 608         }\r
 609         else if (scsiDev.msgOut == 0x05)\r
 610         {\r
 611                 // Initiate Detected Error\r
 612                 // Ignore for now\r
 613         }\r
 614         else if (scsiDev.msgOut == 0x0F)\r
 615         {\r
 616                 // INITIATE RECOVERY\r
 617                 // Ignore for now\r
 618         }\r
 619         else if (scsiDev.msgOut == 0x10)\r
 620         {\r
 621                 // RELEASE RECOVERY\r
 622                 // Ignore for now\r
 623                 enter_BusFree();\r
 624         }\r
 625         else if (scsiDev.msgOut == MSG_REJECT)\r
 626         {\r
 627                 // Message Reject\r
 628                 // Oh well.\r
 629                 scsiDev.resetFlag = 1;\r
 630         }\r
 631         else if (scsiDev.msgOut == 0x08)\r
 632         {\r
 633                 // NOP\r
 634         }\r
 635         else if (scsiDev.msgOut == 0x09)\r
 636         {\r
 637                 // Message Parity Error\r
 638                 // Go back and re-send the last message.\r
 639                 scsiDev.phase = MESSAGE_IN;\r
 640         }\r
 641         else if (scsiDev.msgOut & 0x80) // 0x80 -> 0xFF\r
 642         {\r
 643                 // IDENTIFY\r
 644                 // We don't disconnect, so ignore disconnect privilege.\r
 645                 if ((scsiDev.msgOut & 0x18) || // Reserved bits set.\r
 646                         (scsiDev.msgOut & 0x20)  || // We don't have any target routines!\r
 647                         (scsiDev.msgOut & 0x7) // We only support LUN 0!\r
 648                         )\r
 649                 {\r
 650                         messageReject();\r
 651                 }\r
 652         }\r
 653         else if (scsiDev.msgOut >= 0x20 && scsiDev.msgOut <= 0x2F)\r
 654         {\r
 655                 // Two byte message. We don't support these. read and discard.\r
 656                 scsiReadByte();\r
 657         }\r
 658         else if (scsiDev.msgOut == 0x01)\r
 659         {\r
 660                 int i;\r
 661 \r
 662                 // Extended message.\r
 663                 int msgLen = scsiReadByte();\r
 664                 if (msgLen == 0) msgLen = 256;\r
 665                 for (i = 0; i < msgLen && !scsiDev.resetFlag; ++i)\r
 666                 {\r
 667                         // Discard bytes.\r
 668                         scsiReadByte();\r
 669                 }\r
 670 \r
 671                 // We don't support ANY extended messages.\r
 672                 // Modify Data Pointer:  We don't support reselection.\r
 673                 // Wide Data Transfer Request: No. 8bit only.\r
 674                 // Synchronous data transfer request. No, we can't do that.\r
 675                 // We don't support any 2-byte messages either.\r
 676                 // And we don't support any optional 1-byte messages.\r
 677                 // In each case, the correct response is MESSAGE REJECT.\r
 678                 messageReject();\r
 679         }\r
 680         else\r
 681         {\r
 682                 messageReject();\r
 683         }\r
 684 \r
 685         // Re-check the ATN flag in case it stays asserted.\r
 686         scsiDev.atnFlag |= SCSI_ReadPin(SCSI_ATN_INT);\r
 687 }\r
 688 \r
 689 void scsiPoll(void)\r
 690 {\r
 691         if (scsiDev.resetFlag)\r
 692         {\r
 693                 scsiReset();\r
 694                 if ((scsiDev.resetFlag = SCSI_ReadPin(SCSI_RST_INT)))\r
 695                 {\r
 696                         // Still in reset phase. Do not try and process any commands.\r
 697                         return;\r
 698                 }\r
 699         }\r
 700 \r
 701         switch (scsiDev.phase)\r
 702         {\r
 703         case BUS_FREE:\r
 704                 if (SCSI_ReadPin(SCSI_In_BSY))\r
 705                 {\r
 706                         scsiDev.phase = BUS_BUSY;\r
 707                 }\r
 708                 // The Arbitration phase is optional for SCSI1/SASI hosts if there is only\r
 709                 // one initiator in the chain. Support this by moving\r
 710                 // straight to selection if SEL is asserted.\r
 711                 // ie. the initiator won't assert BSY and it's own ID before moving to selection.\r
 712                 else if (SCSI_ReadPin(SCSI_In_SEL))\r
 713                 {\r
 714                         enter_SelectionPhase();\r
 715                 }\r
 716         break;\r
 717 \r
 718         case BUS_BUSY:\r
 719                 // Someone is using the bus. Perhaps they are trying to\r
 720                 // select us.\r
 721                 if (SCSI_ReadPin(SCSI_In_SEL))\r
 722                 {\r
 723                         enter_SelectionPhase();\r
 724                 }\r
 725                 else if (!SCSI_ReadPin(SCSI_In_BSY))\r
 726                 {\r
 727                         scsiDev.phase = BUS_FREE;\r
 728                 }\r
 729         break;\r
 730 \r
 731         case ARBITRATION:\r
 732                 // TODO Support reselection.\r
 733                 break;\r
 734 \r
 735         case SELECTION:\r
 736                 process_SelectionPhase();\r
 737         break;\r
 738 \r
 739         case RESELECTION:\r
 740                 // Not currently supported!\r
 741         break;\r
 742 \r
 743         case COMMAND:\r
 744                 // Do not check ATN here. SCSI 1 & 2 initiators must set ATN\r
 745                 // and SEL together upon entering the selection phase if they\r
 746                 // want to send a message (IDENTIFY) immediately.\r
 747                 if (scsiDev.atnFlag)\r
 748                 {\r
 749                         process_MessageOut();\r
 750                 }\r
 751                 else\r
 752                 {\r
 753                         process_Command();\r
 754                 }\r
 755         break;\r
 756 \r
 757         case DATA_IN:\r
 758                 scsiDev.atnFlag |= SCSI_ReadPin(SCSI_ATN_INT);\r
 759                 if (scsiDev.atnFlag)\r
 760                 {\r
 761                         process_MessageOut();\r
 762                 }\r
 763                 else\r
 764                 {\r
 765                         process_DataIn();\r
 766                 }\r
 767         break;\r
 768 \r
 769         case DATA_OUT:\r
 770                 scsiDev.atnFlag |= SCSI_ReadPin(SCSI_ATN_INT);\r
 771                 if (scsiDev.atnFlag)\r
 772                 {\r
 773                         process_MessageOut();\r
 774                 }\r
 775                 else\r
 776                 {\r
 777                         process_DataOut();\r
 778                 }\r
 779         break;\r
 780 \r
 781         case STATUS:\r
 782                 scsiDev.atnFlag |= SCSI_ReadPin(SCSI_ATN_INT);\r
 783                 if (scsiDev.atnFlag)\r
 784                 {\r
 785                         process_MessageOut();\r
 786                 }\r
 787                 else\r
 788                 {\r
 789                         process_Status();\r
 790                 }\r
 791         break;\r
 792 \r
 793         case MESSAGE_IN:\r
 794                 scsiDev.atnFlag |= SCSI_ReadPin(SCSI_ATN_INT);\r
 795                 if (scsiDev.atnFlag)\r
 796                 {\r
 797                         process_MessageOut();\r
 798                 }\r
 799                 else\r
 800                 {\r
 801                         process_MessageIn();\r
 802                 }\r
 803 \r
 804         break;\r
 805 \r
 806         case MESSAGE_OUT:\r
 807                 process_MessageOut();\r
 808         break;\r
 809         }\r
 810 }\r
 811 \r
 812 void scsiInit()\r
 813 {\r
 814         scsiDev.scsiIdMask = 1 << (config->scsiId);\r
 815 \r
 816         scsiDev.atnFlag = 0;\r
 817         scsiDev.resetFlag = 1;\r
 818         scsiDev.phase = BUS_FREE;\r
 819         scsiDev.reservedId = -1;\r
 820         scsiDev.reserverId = -1;\r
 821         scsiDev.unitAttention = POWER_ON_RESET;\r
 822 }\r
 823 \r