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