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