software/SCSI2SD/SCSI2SD.cydsn/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         scsiEnterPhase(BUS_FREE);\r
  52 \r
  53         ledOff();\r
  54 \r
  55         scsiDev.phase = BUS_FREE;\r
  56         SCSI_ClearPin(SCSI_Out_BSY);\r
  57 }\r
  58 \r
  59 static void enter_MessageIn(uint8 message)\r
  60 {\r
  61         scsiDev.msgIn = message;\r
  62         scsiDev.phase = MESSAGE_IN;\r
  63 }\r
  64 \r
  65 static void process_MessageIn()\r
  66 {\r
  67         scsiEnterPhase(MESSAGE_IN);\r
  68         scsiWriteByte(scsiDev.msgIn);\r
  69 \r
  70         if (scsiDev.atnFlag)\r
  71         {\r
  72                 // If there was a parity error, we go\r
  73                 // back to MESSAGE_OUT first, get out parity error message, then come\r
  74                 // back here.\r
  75         }\r
  76         else /*if (scsiDev.msgIn == MSG_COMMAND_COMPLETE)*/\r
  77         {\r
  78                 enter_BusFree();\r
  79         }\r
  80 }\r
  81 \r
  82 static void messageReject()\r
  83 {\r
  84         scsiEnterPhase(MESSAGE_IN);\r
  85         scsiWriteByte(MSG_REJECT);\r
  86 }\r
  87 \r
  88 static void enter_Status(uint8 status)\r
  89 {\r
  90         scsiDev.status = status;\r
  91         scsiDev.phase = STATUS;\r
  92 }\r
  93 \r
  94 static void process_Status()\r
  95 {\r
  96         scsiEnterPhase(STATUS);\r
  97         scsiWriteByte(scsiDev.status);\r
  98         \r
  99         #ifdef MM_DEBUG\r
 100         scsiDev.lastStatus = scsiDev.status;\r
 101         scsiDev.lastSense = scsiDev.sense.code;\r
 102         #endif\r
 103 \r
 104         // Command Complete occurs AFTER a valid status has been\r
 105         // sent. then we go bus-free.\r
 106         enter_MessageIn(MSG_COMMAND_COMPLETE);\r
 107 }\r
 108 \r
 109 static void enter_DataIn(int len)\r
 110 {\r
 111         scsiDev.dataLen = len;\r
 112         scsiDev.phase = DATA_IN;\r
 113 }\r
 114 \r
 115 static void process_DataIn()\r
 116 {\r
 117         uint32 len;\r
 118         \r
 119         if (scsiDev.dataLen > sizeof(scsiDev.data))\r
 120         {\r
 121                 scsiDev.dataLen = sizeof(scsiDev.data);\r
 122         }\r
 123 \r
 124         len = scsiDev.dataLen - scsiDev.dataPtr;\r
 125         if (len > 0)\r
 126         {\r
 127                 scsiEnterPhase(DATA_IN);\r
 128                 scsiWrite(scsiDev.data + scsiDev.dataPtr, len);\r
 129                 scsiDev.dataPtr += len;\r
 130         }\r
 131 \r
 132         if ((scsiDev.dataPtr >= scsiDev.dataLen) &&\r
 133                 (transfer.currentBlock == transfer.blocks))\r
 134         {\r
 135                 enter_Status(GOOD);\r
 136         }\r
 137 }\r
 138 \r
 139 static void process_DataOut()\r
 140 {\r
 141         uint32 len;\r
 142         \r
 143         if (scsiDev.dataLen > sizeof(scsiDev.data))\r
 144         {\r
 145                 scsiDev.dataLen = sizeof(scsiDev.data);\r
 146         }\r
 147 \r
 148         scsiDev.parityError = 0;\r
 149         len = scsiDev.dataLen - scsiDev.dataPtr;\r
 150         if (len > 0)\r
 151         {\r
 152                 scsiEnterPhase(DATA_OUT);\r
 153 \r
 154                 scsiRead(scsiDev.data + scsiDev.dataPtr, len);\r
 155                 scsiDev.dataPtr += len;\r
 156 \r
 157                 // TODO re-implement parity checking\r
 158                 if (0 && scsiDev.parityError && config->enableParity)\r
 159                 {\r
 160                         scsiDev.sense.code = ABORTED_COMMAND;\r
 161                         scsiDev.sense.asc = SCSI_PARITY_ERROR;\r
 162                         enter_Status(CHECK_CONDITION);\r
 163                 }\r
 164         }\r
 165 \r
 166         if ((scsiDev.dataPtr >= scsiDev.dataLen) &&\r
 167                 (transfer.currentBlock == transfer.blocks))\r
 168         {\r
 169                 enter_Status(GOOD);\r
 170         }\r
 171 }\r
 172 \r
 173 static const uint8 CmdGroupBytes[8] = {6, 10, 10, 6, 6, 12, 6, 6};\r
 174 static void process_Command()\r
 175 {\r
 176         int group;\r
 177         int cmdSize;\r
 178         uint8 command;\r
 179         uint8 lun;\r
 180         \r
 181         scsiEnterPhase(COMMAND);\r
 182         scsiDev.parityError = 0;\r
 183 \r
 184         memset(scsiDev.cdb, 0, sizeof(scsiDev.cdb));\r
 185         scsiDev.cdb[0] = scsiReadByte();\r
 186 \r
 187         group = scsiDev.cdb[0] >> 5;\r
 188         cmdSize = CmdGroupBytes[group];\r
 189         scsiRead(scsiDev.cdb + 1, cmdSize - 1);\r
 190 \r
 191         command = scsiDev.cdb[0];\r
 192         lun = scsiDev.cdb[1] >> 5;\r
 193 \r
 194         if (scsiDev.parityError)\r
 195         {\r
 196                 scsiDev.sense.code = ABORTED_COMMAND;\r
 197                 scsiDev.sense.asc = SCSI_PARITY_ERROR;\r
 198                 enter_Status(CHECK_CONDITION);\r
 199         }\r
 200         else if (command == 0x12)\r
 201         {\r
 202                 scsiInquiry();\r
 203         }\r
 204         else if (command == 0x03)\r
 205         {\r
 206                 // REQUEST SENSE\r
 207                 uint32 allocLength = scsiDev.cdb[4];\r
 208                 if (allocLength == 0) allocLength = 256;\r
 209                 memset(scsiDev.data, 0, 18);\r
 210                 scsiDev.data[0] = 0xF0;\r
 211                 scsiDev.data[2] = scsiDev.sense.code & 0x0F;\r
 212 \r
 213                 // TODO populate "information" field with requested LBA.\r
 214                 // TODO support more detailed sense data ?\r
 215 \r
 216                 scsiDev.data[12] = scsiDev.sense.asc >> 8;\r
 217                 scsiDev.data[13] = scsiDev.sense.asc;\r
 218 \r
 219                 // Silently truncate results. SCSI-2 spec 8.2.14.\r
 220                 enter_DataIn(allocLength < 18 ? allocLength : 18);\r
 221 \r
 222                 // This is a good time to clear out old sense information.\r
 223                 scsiDev.sense.code = NO_SENSE;\r
 224                 scsiDev.sense.asc = NO_ADDITIONAL_SENSE_INFORMATION;\r
 225         }\r
 226         // Some old SCSI drivers do NOT properly support\r
 227         // unitAttention. OTOH, Linux seems to require it\r
 228         // confirmed LCIII with unknown scsi driver fials here.\r
 229         else if (scsiDev.unitAttention && config->enableUnitAttention)\r
 230         {\r
 231                 scsiDev.sense.code = UNIT_ATTENTION;\r
 232                 scsiDev.sense.asc = scsiDev.unitAttention;\r
 233                 enter_Status(CHECK_CONDITION);\r
 234         }\r
 235         else if (lun)\r
 236         {\r
 237                 scsiDev.sense.code = ILLEGAL_REQUEST;\r
 238                 scsiDev.sense.asc = LOGICAL_UNIT_NOT_SUPPORTED;\r
 239                 enter_Status(CHECK_CONDITION);\r
 240         }\r
 241         else if (command == 0x17 || command == 0x16)\r
 242         {\r
 243                 doReserveRelease();\r
 244         }\r
 245         else if ((scsiDev.reservedId >= 0) &&\r
 246                 (scsiDev.reservedId != scsiDev.initiatorId))\r
 247         {\r
 248                 enter_Status(CONFLICT);\r
 249         }\r
 250         else if (command == 0x1C)\r
 251         {\r
 252                 scsiReceiveDiagnostic();\r
 253         }\r
 254         else if (command == 0x1D)\r
 255         {\r
 256                 scsiSendDiagnostic();\r
 257         }\r
 258         else if (\r
 259                 !scsiModeCommand() &&\r
 260                 !scsiDiskCommand())\r
 261         {\r
 262                 scsiDev.sense.code = ILLEGAL_REQUEST;\r
 263                 scsiDev.sense.asc = INVALID_COMMAND_OPERATION_CODE;\r
 264                 enter_Status(CHECK_CONDITION);\r
 265         }\r
 266 \r
 267         // Successful\r
 268         if (scsiDev.phase == COMMAND) // No status set, and not in DATA_IN\r
 269         {\r
 270                 enter_Status(GOOD);\r
 271         }\r
 272 }\r
 273 \r
 274 static void doReserveRelease()\r
 275 {\r
 276         int extentReservation = scsiDev.cdb[1] & 1;\r
 277         int thirdPty = scsiDev.cdb[1] & 0x10;\r
 278         int thirdPtyId = (scsiDev.cdb[1] >> 1) & 0x7;\r
 279         uint8 command = scsiDev.cdb[0];\r
 280 \r
 281         int canRelease =\r
 282                 (!thirdPty && (scsiDev.initiatorId == scsiDev.reservedId)) ||\r
 283                         (thirdPty &&\r
 284                                 (scsiDev.reserverId == scsiDev.initiatorId) &&\r
 285                                 (scsiDev.reservedId == thirdPtyId)\r
 286                         );\r
 287 \r
 288         if (extentReservation)\r
 289         {\r
 290                 // Not supported.\r
 291                 scsiDev.sense.code = ILLEGAL_REQUEST;\r
 292                 scsiDev.sense.asc = INVALID_FIELD_IN_CDB;\r
 293                 enter_Status(CHECK_CONDITION);\r
 294         }\r
 295         else if (command == 0x17) // release\r
 296         {\r
 297                 if ((scsiDev.reservedId < 0) || canRelease)\r
 298                 {\r
 299                         scsiDev.reservedId = -1;\r
 300                         scsiDev.reserverId = -1;\r
 301                 }\r
 302                 else\r
 303                 {\r
 304                         enter_Status(CONFLICT);\r
 305                 }\r
 306         }\r
 307         else // assume reserve.\r
 308         {\r
 309                 if ((scsiDev.reservedId < 0) || canRelease)\r
 310                 {\r
 311                         scsiDev.reserverId = scsiDev.initiatorId;\r
 312                         if (thirdPty)\r
 313                         {\r
 314                                 scsiDev.reservedId = thirdPtyId;\r
 315                         }\r
 316                         else\r
 317                         {\r
 318                                 scsiDev.reservedId = scsiDev.initiatorId;\r
 319                         }\r
 320                 }\r
 321                 else\r
 322                 {\r
 323                         // Already reserved by someone else!\r
 324                         enter_Status(CONFLICT);\r
 325                 }\r
 326         }\r
 327 }\r
 328 \r
 329 static void scsiReset()\r
 330 {\r
 331 #ifdef MM_DEBUG\r
 332         scsiDev.rstCount++;\r
 333 #endif\r
 334         ledOff();\r
 335         // done in verilog SCSI_Out_DBx_Write(0);\r
 336         SCSI_CTL_IO_Write(0);\r
 337         SCSI_ClearPin(SCSI_Out_ATN);\r
 338         SCSI_ClearPin(SCSI_Out_BSY);\r
 339         SCSI_ClearPin(SCSI_Out_ACK);\r
 340         SCSI_ClearPin(SCSI_Out_RST);\r
 341         SCSI_ClearPin(SCSI_Out_SEL);\r
 342         SCSI_ClearPin(SCSI_Out_REQ);\r
 343         SCSI_ClearPin(SCSI_Out_MSG);\r
 344         SCSI_ClearPin(SCSI_Out_CD);\r
 345 \r
 346         scsiDev.parityError = 0;\r
 347         scsiDev.phase = BUS_FREE;\r
 348 \r
 349         if (scsiDev.unitAttention != POWER_ON_RESET)\r
 350         {\r
 351                 scsiDev.unitAttention = SCSI_BUS_RESET;\r
 352         }\r
 353         scsiDev.reservedId = -1;\r
 354         scsiDev.reserverId = -1;\r
 355         scsiDev.sense.code = NO_SENSE;\r
 356         scsiDev.sense.asc = NO_ADDITIONAL_SENSE_INFORMATION;\r
 357         scsiDiskReset();\r
 358 \r
 359         // Sleep to allow the bus to settle down a bit.\r
 360         // We must be ready again within the "Reset to selection time" of\r
 361         // 250ms.\r
 362         // There is no guarantee that the RST line will be negated by then.\r
 363         // NOTE: We could be connected and powered by USB for configuration,\r
 364         // in which case TERMPWR cannot be supplied, and reset will ALWAYS\r
 365         // be true.\r
 366         CyDelay(10); // 10ms.\r
 367         scsiDev.resetFlag = SCSI_ReadPin(SCSI_RST_INT);\r
 368         scsiDev.atnFlag = 0;\r
 369 }\r
 370 \r
 371 static void enter_SelectionPhase()\r
 372 {\r
 373         // Ignore stale versions of this flag, but ensure we know the\r
 374         // current value if the flag is still set.\r
 375         scsiDev.atnFlag = 0;\r
 376         scsiDev.parityError = 0;\r
 377         scsiDev.dataPtr = 0;\r
 378         scsiDev.savedDataPtr = 0;\r
 379         scsiDev.dataLen = 0;\r
 380         scsiDev.status = GOOD;\r
 381         scsiDev.phase = SELECTION;\r
 382 \r
 383         transfer.blocks = 0;\r
 384         transfer.currentBlock = 0;\r
 385 }\r
 386 \r
 387 static void process_SelectionPhase()\r
 388 {\r
 389         int sel = SCSI_ReadPin(SCSI_In_SEL);\r
 390         int bsy = SCSI_ReadPin(SCSI_In_BSY);\r
 391 \r
 392         // Only read these pins AFTER SEL and BSY - we don't want to catch them\r
 393         // during a transition period.\r
 394         uint8 mask = scsiReadDBxPins();\r
 395         int maskBitCount = countBits(mask);\r
 396         int goodParity = (Lookup_OddParity[mask] == SCSI_ReadPin(SCSI_In_DBP));\r
 397 \r
 398         if (!bsy && sel &&\r
 399                 (mask & scsiDev.scsiIdMask) &&\r
 400                 (goodParity || !config->enableParity) && (maskBitCount <= 2))\r
 401         {\r
 402                 // Do we enter MESSAGE OUT immediately ? SCSI 1 and 2 standards says\r
 403                 // move to MESSAGE OUT if ATN is true before we release BSY.\r
 404                 // The initiate should assert ATN with SEL.\r
 405                 scsiDev.atnFlag = SCSI_ReadPin(SCSI_ATN_INT);\r
 406 \r
 407                 // We've been selected!\r
 408                 // Assert BSY - Selection success!\r
 409                 // must happen within 200us (Selection abort time) of seeing our\r
 410                 // ID + SEL.\r
 411                 // (Note: the initiator will be waiting the "Selection time-out delay"\r
 412                 // for our BSY response, which is actually a very generous 250ms)\r
 413                 SCSI_SetPin(SCSI_Out_BSY);\r
 414                 ledOn();\r
 415 \r
 416                 #ifdef MM_DEBUG\r
 417                 scsiDev.selCount++;\r
 418                 #endif\r
 419 \r
 420                 // Wait until the end of the selection phase.\r
 421                 while (!scsiDev.resetFlag)\r
 422                 {\r
 423                         if (!SCSI_ReadPin(SCSI_In_SEL))\r
 424                         {\r
 425                                 break;\r
 426                         }\r
 427                 }\r
 428                 // Last chance for the ATN signal! The initiator should have set this\r
 429                 // previously, but we try and be a little tolerant. This is required\r
 430                 // for the LCIII to work. I assume ATN is being set before the\r
 431                 // initiator releases SEL.\r
 432                 scsiDev.atnFlag = SCSI_ReadPin(SCSI_ATN_INT);\r
 433 \r
 434 \r
 435                 // Save our initiator now that we're no longer in a time-critical\r
 436                 // section.\r
 437                 // SCSI1/SASI initiators may not set their own ID.\r
 438                 if (maskBitCount == 2)\r
 439                 {\r
 440                         int i;\r
 441                         uint8 initiatorMask = mask ^ scsiDev.scsiIdMask;\r
 442                         scsiDev.initiatorId = 0;\r
 443                         for (i = 0; i < 8; ++i)\r
 444                         {\r
 445                                 if (initiatorMask & (1 << i))\r
 446                                 {\r
 447                                         scsiDev.initiatorId = i;\r
 448                                         break;\r
 449                                 }\r
 450                         }\r
 451                 }\r
 452                 else\r
 453                 {\r
 454                         scsiDev.initiatorId = -1;\r
 455                 }\r
 456 \r
 457                 scsiDev.phase = COMMAND;\r
 458         }\r
 459         else if (!sel)\r
 460         {\r
 461                 scsiDev.phase = BUS_BUSY;\r
 462         }\r
 463 }\r
 464 \r
 465 static void process_MessageOut()\r
 466 {\r
 467         scsiEnterPhase(MESSAGE_OUT);\r
 468 \r
 469         scsiDev.atnFlag = 0;\r
 470         scsiDev.parityError = 0;\r
 471         scsiDev.msgOut = scsiReadByte();\r
 472 #ifdef MM_DEBUG\r
 473         scsiDev.msgCount++;\r
 474 #endif\r
 475 \r
 476         if (scsiDev.parityError)\r
 477         {\r
 478                 // Skip the remaining message bytes, and then start the MESSAGE_OUT\r
 479                 // phase again from the start. The initiator will re-send the\r
 480                 // same set of messages.\r
 481                 while (SCSI_ReadPin(SCSI_ATN_INT) && !scsiDev.resetFlag)\r
 482                 {\r
 483                         scsiReadByte();\r
 484                 }\r
 485 \r
 486                 // Go-back and try the message again.\r
 487                 scsiDev.atnFlag = 1;\r
 488                 scsiDev.parityError = 0;\r
 489         }\r
 490         else if (scsiDev.msgOut == 0x00)\r
 491         {\r
 492                 // COMMAND COMPLETE. but why would the target be receiving this ? nfi.\r
 493                 enter_BusFree();\r
 494         }\r
 495         else if (scsiDev.msgOut == 0x06)\r
 496         {\r
 497                 // ABORT\r
 498                 scsiDiskReset();\r
 499                 enter_BusFree();\r
 500         }\r
 501         else if (scsiDev.msgOut == 0x0C)\r
 502         {\r
 503                 // BUS DEVICE RESET\r
 504 \r
 505                 scsiDiskReset();\r
 506 \r
 507                 scsiDev.unitAttention = SCSI_BUS_RESET;\r
 508 \r
 509                 // ANY initiator can reset the reservation state via this message.\r
 510                 scsiDev.reservedId = -1;\r
 511                 scsiDev.reserverId = -1;\r
 512                 enter_BusFree();\r
 513         }\r
 514         else if (scsiDev.msgOut == 0x05)\r
 515         {\r
 516                 // Initiate Detected Error\r
 517                 // Ignore for now\r
 518         }\r
 519         else if (scsiDev.msgOut == 0x0F)\r
 520         {\r
 521                 // INITIATE RECOVERY\r
 522                 // Ignore for now\r
 523         }\r
 524         else if (scsiDev.msgOut == 0x10)\r
 525         {\r
 526                 // RELEASE RECOVERY\r
 527                 // Ignore for now\r
 528                 enter_BusFree();\r
 529         }\r
 530         else if (scsiDev.msgOut == MSG_REJECT)\r
 531         {\r
 532                 // Message Reject\r
 533                 // Oh well.\r
 534                 scsiDev.resetFlag = 1;\r
 535         }\r
 536         else if (scsiDev.msgOut == 0x08)\r
 537         {\r
 538                 // NOP\r
 539         }\r
 540         else if (scsiDev.msgOut == 0x09)\r
 541         {\r
 542                 // Message Parity Error\r
 543                 // Go back and re-send the last message.\r
 544                 scsiDev.phase = MESSAGE_IN;\r
 545         }\r
 546         else if (scsiDev.msgOut & 0x80) // 0x80 -> 0xFF\r
 547         {\r
 548                 // IDENTIFY\r
 549                 // We don't disconnect, so ignore disconnect privilege.\r
 550                 if ((scsiDev.msgOut & 0x18) || // Reserved bits set.\r
 551                         (scsiDev.msgOut & 0x20)  || // We don't have any target routines!\r
 552                         (scsiDev.msgOut & 0x7) // We only support LUN 0!\r
 553                         )\r
 554                 {\r
 555                         messageReject();\r
 556                 }\r
 557         }\r
 558         else if (scsiDev.msgOut >= 0x20 && scsiDev.msgOut <= 0x2F)\r
 559         {\r
 560                 // Two byte message. We don't support these. read and discard.\r
 561                 scsiReadByte();\r
 562         }\r
 563         else if (scsiDev.msgOut == 0x01)\r
 564         {\r
 565                 int i;\r
 566 \r
 567                 // Extended message.\r
 568                 int msgLen = scsiReadByte();\r
 569                 if (msgLen == 0) msgLen = 256;\r
 570                 for (i = 0; i < msgLen && !scsiDev.resetFlag; ++i)\r
 571                 {\r
 572                         // Discard bytes.\r
 573                         scsiReadByte();\r
 574                 }\r
 575 \r
 576                 // We don't support ANY extended messages.\r
 577                 // Modify Data Pointer:  We don't support reselection.\r
 578                 // Wide Data Transfer Request: No. 8bit only.\r
 579                 // Synchronous data transfer request. No, we can't do that.\r
 580                 // We don't support any 2-byte messages either.\r
 581                 // And we don't support any optional 1-byte messages.\r
 582                 // In each case, the correct response is MESSAGE REJECT.\r
 583                 messageReject();\r
 584         }\r
 585         else\r
 586         {\r
 587                 messageReject();\r
 588         }\r
 589 \r
 590         // Re-check the ATN flag in case it stays asserted.\r
 591         scsiDev.atnFlag |= SCSI_ReadPin(SCSI_ATN_INT);\r
 592 }\r
 593 \r
 594 void scsiPoll(void)\r
 595 {\r
 596         if (scsiDev.resetFlag)\r
 597         {\r
 598                 scsiReset();\r
 599         }\r
 600 \r
 601         switch (scsiDev.phase)\r
 602         {\r
 603         case BUS_FREE:\r
 604                 if (SCSI_ReadPin(SCSI_In_BSY))\r
 605                 {\r
 606                         scsiDev.phase = BUS_BUSY;\r
 607                 }\r
 608                 // The Arbitration phase is optional for SCSI1/SASI hosts if there is only\r
 609                 // one initiator in the chain. Support this by moving\r
 610                 // straight to selection if SEL is asserted.\r
 611                 // ie. the initiator won't assert BSY and it's own ID before moving to selection.\r
 612                 else if (SCSI_ReadPin(SCSI_In_SEL))\r
 613                 {\r
 614                         enter_SelectionPhase();\r
 615                 }\r
 616         break;\r
 617 \r
 618         case BUS_BUSY:\r
 619                 // Someone is using the bus. Perhaps they are trying to\r
 620                 // select us.\r
 621                 if (SCSI_ReadPin(SCSI_In_SEL))\r
 622                 {\r
 623                         enter_SelectionPhase();\r
 624                 }\r
 625                 else if (!SCSI_ReadPin(SCSI_In_BSY))\r
 626                 {\r
 627                         scsiDev.phase = BUS_FREE;\r
 628                 }\r
 629         break;\r
 630 \r
 631         case ARBITRATION:\r
 632                 // TODO Support reselection.\r
 633                 break;\r
 634 \r
 635         case SELECTION:\r
 636                 process_SelectionPhase();\r
 637         break;\r
 638 \r
 639         case RESELECTION:\r
 640                 // Not currently supported!\r
 641         break;\r
 642 \r
 643         case COMMAND:\r
 644                 // Do not check ATN here. SCSI 1 & 2 initiators must set ATN\r
 645                 // and SEL together upon entering the selection phase if they\r
 646                 // want to send a message (IDENTIFY) immediately.\r
 647                 if (scsiDev.atnFlag)\r
 648                 {\r
 649                         process_MessageOut();\r
 650                 }\r
 651                 else\r
 652                 {\r
 653                         process_Command();\r
 654                 }\r
 655         break;\r
 656 \r
 657         case DATA_IN:\r
 658                 scsiDev.atnFlag |= SCSI_ReadPin(SCSI_ATN_INT);\r
 659                 if (scsiDev.atnFlag)\r
 660                 {\r
 661                         process_MessageOut();\r
 662                 }\r
 663                 else\r
 664                 {\r
 665                         process_DataIn();\r
 666                 }\r
 667         break;\r
 668 \r
 669         case DATA_OUT:\r
 670                 scsiDev.atnFlag |= SCSI_ReadPin(SCSI_ATN_INT);\r
 671                 if (scsiDev.atnFlag)\r
 672                 {\r
 673                         process_MessageOut();\r
 674                 }\r
 675                 else\r
 676                 {\r
 677                         process_DataOut();\r
 678                 }\r
 679         break;\r
 680 \r
 681         case STATUS:\r
 682                 scsiDev.atnFlag |= SCSI_ReadPin(SCSI_ATN_INT);\r
 683                 if (scsiDev.atnFlag)\r
 684                 {\r
 685                         process_MessageOut();\r
 686                 }\r
 687                 else\r
 688                 {\r
 689                         process_Status();\r
 690                 }\r
 691         break;\r
 692 \r
 693         case MESSAGE_IN:\r
 694                 scsiDev.atnFlag |= SCSI_ReadPin(SCSI_ATN_INT);\r
 695                 if (scsiDev.atnFlag)\r
 696                 {\r
 697                         process_MessageOut();\r
 698                 }\r
 699                 else\r
 700                 {\r
 701                         process_MessageIn();\r
 702                 }\r
 703 \r
 704         break;\r
 705 \r
 706         case MESSAGE_OUT:\r
 707                 process_MessageOut();\r
 708         break;\r
 709         }\r
 710 }\r
 711 \r
 712 void scsiInit()\r
 713 {\r
 714         scsiDev.scsiIdMask = 1 << (config->scsiId);\r
 715 \r
 716         scsiDev.atnFlag = 0;\r
 717         scsiDev.resetFlag = 1;\r
 718         scsiDev.phase = BUS_FREE;\r
 719         scsiDev.reservedId = -1;\r
 720         scsiDev.reserverId = -1;\r
 721         scsiDev.unitAttention = POWER_ON_RESET;\r
 722 }\r
 723 \r