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SCSI2SD/software/SCSI2SD/src/scsi.c

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// Copyright (C) 2014 Michael McMaster <michael@codesrc.com>
//
// This file is part of SCSI2SD.
//
// SCSI2SD is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// SCSI2SD is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with SCSI2SD. If not, see <http://www.gnu.org/licenses/>.
#include "device.h"
#include "scsi.h"
#include "scsiPhy.h"
#include "config.h"
#include "bits.h"
#include "diagnostic.h"
#include "disk.h"
#include "inquiry.h"
#include "led.h"
#include "mode.h"
#include "disk.h"
#include <string.h>
// Global SCSI device state.
ScsiDevice scsiDev;
static void enter_SelectionPhase(void);
static void process_SelectionPhase(void);
static void enter_BusFree(void);
static void enter_MessageIn(uint8 message);
static void process_MessageIn(void);
static void enter_Status(uint8 status);
static void process_Status(void);
static void enter_DataIn(int len);
static void process_DataIn(void);
static void process_DataOut(void);
static void process_Command(void);
static void doReserveRelease(void);
static void enter_BusFree()
{
// This delay probably isn't needed for most SCSI hosts, but it won't
// hurt either. It's possible some of the samplers needed this delay.
CyDelayUs(2);
SCSI_ClearPin(SCSI_Out_BSY);
// We now have a Bus Clear Delay of 800ns to release remaining signals.
SCSI_CTL_PHASE_Write(0);
// Wait for the initiator to cease driving signals
// Bus settle delay + bus clear delay = 1200ns
CyDelayUs(2);
ledOff();
scsiDev.phase = BUS_FREE;
}
static void enter_MessageIn(uint8 message)
{
scsiDev.msgIn = message;
scsiDev.phase = MESSAGE_IN;
}
static void process_MessageIn()
{
scsiEnterPhase(MESSAGE_IN);
scsiWriteByte(scsiDev.msgIn);
if (scsiDev.atnFlag)
{
// If there was a parity error, we go
// back to MESSAGE_OUT first, get out parity error message, then come
// back here.
}
else if ((scsiDev.msgIn == MSG_LINKED_COMMAND_COMPLETE) ||
(scsiDev.msgIn == MSG_LINKED_COMMAND_COMPLETE_WITH_FLAG))
{
// Go back to the command phase and start again.
scsiDev.phase = COMMAND;
scsiDev.parityError = 0;
scsiDev.dataPtr = 0;
scsiDev.savedDataPtr = 0;
scsiDev.dataLen = 0;
scsiDev.status = GOOD;
transfer.blocks = 0;
transfer.currentBlock = 0;
}
else /*if (scsiDev.msgIn == MSG_COMMAND_COMPLETE)*/
{
enter_BusFree();
}
}
static void messageReject()
{
scsiEnterPhase(MESSAGE_IN);
scsiWriteByte(MSG_REJECT);
}
static void enter_Status(uint8 status)
{
scsiDev.status = status;
scsiDev.phase = STATUS;
scsiDev.lastStatus = scsiDev.status;
scsiDev.lastSense = scsiDev.sense.code;
}
static void process_Status()
{
scsiEnterPhase(STATUS);
uint8 message;
uint8 control = scsiDev.cdb[scsiDev.cdbLen - 1];
if ((scsiDev.status == GOOD) && (control & 0x01))
{
// Linked command.
scsiDev.status = INTERMEDIATE;
if (control & 0x02)
{
message = MSG_LINKED_COMMAND_COMPLETE_WITH_FLAG;
}
else
{
message = MSG_LINKED_COMMAND_COMPLETE;
}
}
else
{
message = MSG_COMMAND_COMPLETE;
}
scsiWriteByte(scsiDev.status);
scsiDev.lastStatus = scsiDev.status;
scsiDev.lastSense = scsiDev.sense.code;
// Command Complete occurs AFTER a valid status has been
// sent. then we go bus-free.
enter_MessageIn(message);
}
static void enter_DataIn(int len)
{
scsiDev.dataLen = len;
scsiDev.phase = DATA_IN;
}
static void process_DataIn()
{
uint32 len;
if (scsiDev.dataLen > sizeof(scsiDev.data))
{
scsiDev.dataLen = sizeof(scsiDev.data);
}
len = scsiDev.dataLen - scsiDev.dataPtr;
if (len > 0)
{
scsiEnterPhase(DATA_IN);
scsiWrite(scsiDev.data + scsiDev.dataPtr, len);
scsiDev.dataPtr += len;
}
if ((scsiDev.dataPtr >= scsiDev.dataLen) &&
(transfer.currentBlock == transfer.blocks))
{
enter_Status(GOOD);
}
}
static void process_DataOut()
{
uint32 len;
if (scsiDev.dataLen > sizeof(scsiDev.data))
{
scsiDev.dataLen = sizeof(scsiDev.data);
}
scsiDev.parityError = 0;
len = scsiDev.dataLen - scsiDev.dataPtr;
if (len > 0)
{
scsiEnterPhase(DATA_OUT);
scsiRead(scsiDev.data + scsiDev.dataPtr, len);
scsiDev.dataPtr += len;
if (scsiDev.parityError && config->enableParity)
{
scsiDev.sense.code = ABORTED_COMMAND;
scsiDev.sense.asc = SCSI_PARITY_ERROR;
enter_Status(CHECK_CONDITION);
}
}
if ((scsiDev.dataPtr >= scsiDev.dataLen) &&
(transfer.currentBlock == transfer.blocks))
{
if (scsiDev.postDataOutHook != NULL)
{
scsiDev.postDataOutHook();
}
else
{
enter_Status(GOOD);
}
}
}
static const uint8 CmdGroupBytes[8] = {6, 10, 10, 6, 6, 12, 6, 6};
static void process_Command()
{
int group;
uint8 command;
uint8 control;
scsiEnterPhase(COMMAND);
scsiDev.parityError = 0;
memset(scsiDev.cdb, 0, sizeof(scsiDev.cdb));
scsiDev.cdb[0] = scsiReadByte();
group = scsiDev.cdb[0] >> 5;
scsiDev.cdbLen = CmdGroupBytes[group];
scsiRead(scsiDev.cdb + 1, scsiDev.cdbLen - 1);
command = scsiDev.cdb[0];
// Prefer LUN's set by IDENTIFY messages for newer hosts.
if (scsiDev.lun < 0)
{
scsiDev.lun = scsiDev.cdb[1] >> 5;
}
control = scsiDev.cdb[scsiDev.cdbLen - 1];
scsiDev.cmdCount++;
if (scsiDev.resetFlag)
{
// Don't log bogus commands
scsiDev.cmdCount--;
memset(scsiDev.cdb, 0xff, sizeof(scsiDev.cdb));
return;
}
else if (scsiDev.parityError)
{
scsiDev.sense.code = ABORTED_COMMAND;
scsiDev.sense.asc = SCSI_PARITY_ERROR;
enter_Status(CHECK_CONDITION);
}
else if ((control & 0x02) && ((control & 0x01) == 0))
{
// FLAG set without LINK flag.
scsiDev.sense.code = ILLEGAL_REQUEST;
scsiDev.sense.asc = INVALID_FIELD_IN_CDB;
enter_Status(CHECK_CONDITION);
}
else if (command == 0x12)
{
scsiInquiry();
}
else if (command == 0x03)
{
// REQUEST SENSE
uint32 allocLength = scsiDev.cdb[4];
// As specified by the SASI and SCSI1 standard.
// Newer initiators won't be specifying 0 anyway.
if (allocLength == 0) allocLength = 4;
memset(scsiDev.data, 0, 256); // Max possible alloc length
scsiDev.data[0] = 0xF0;
scsiDev.data[2] = scsiDev.sense.code & 0x0F;
scsiDev.data[3] = transfer.lba >> 24;
scsiDev.data[4] = transfer.lba >> 16;
scsiDev.data[5] = transfer.lba >> 8;
scsiDev.data[6] = transfer.lba;
// Additional bytes if there are errors to report
scsiDev.data[7] = 10; // additional length
scsiDev.data[12] = scsiDev.sense.asc >> 8;
scsiDev.data[13] = scsiDev.sense.asc;
// Silently truncate results. SCSI-2 spec 8.2.14.
enter_DataIn(allocLength);
// This is a good time to clear out old sense information.
scsiDev.sense.code = NO_SENSE;
scsiDev.sense.asc = NO_ADDITIONAL_SENSE_INFORMATION;
}
// Some old SCSI drivers do NOT properly support
// unitAttention. eg. the Mac Plus would trigger a SCSI reset
// on receiving the unit attention response on boot, thus
// triggering another unit attention condition.
else if (scsiDev.unitAttention && config->enableUnitAttention)
{
scsiDev.sense.code = UNIT_ATTENTION;
scsiDev.sense.asc = scsiDev.unitAttention;
// If initiator doesn't do REQUEST SENSE for the next command, then
// data is lost.
scsiDev.unitAttention = 0;
enter_Status(CHECK_CONDITION);
}
else if (scsiDev.lun)
{
scsiDev.sense.code = ILLEGAL_REQUEST;
scsiDev.sense.asc = LOGICAL_UNIT_NOT_SUPPORTED;
enter_Status(CHECK_CONDITION);
}
else if (command == 0x17 || command == 0x16)
{
doReserveRelease();
}
else if ((scsiDev.reservedId >= 0) &&
(scsiDev.reservedId != scsiDev.initiatorId))
{
enter_Status(CONFLICT);
}
else if (command == 0x1C)
{
scsiReceiveDiagnostic();
}
else if (command == 0x1D)
{
scsiSendDiagnostic();
}
else if (command == 0x3C)
{
scsiReadBuffer();
}
else if (
!scsiModeCommand() &&
!scsiDiskCommand())
{
scsiDev.sense.code = ILLEGAL_REQUEST;
scsiDev.sense.asc = INVALID_COMMAND_OPERATION_CODE;
enter_Status(CHECK_CONDITION);
}
// Successful
if (scsiDev.phase == COMMAND) // No status set, and not in DATA_IN
{
enter_Status(GOOD);
}
}
static void doReserveRelease()
{
int extentReservation = scsiDev.cdb[1] & 1;
int thirdPty = scsiDev.cdb[1] & 0x10;
int thirdPtyId = (scsiDev.cdb[1] >> 1) & 0x7;
uint8 command = scsiDev.cdb[0];
int canRelease =
(!thirdPty && (scsiDev.initiatorId == scsiDev.reservedId)) ||
(thirdPty &&
(scsiDev.reserverId == scsiDev.initiatorId) &&
(scsiDev.reservedId == thirdPtyId)
);
if (extentReservation)
{
// Not supported.
scsiDev.sense.code = ILLEGAL_REQUEST;
scsiDev.sense.asc = INVALID_FIELD_IN_CDB;
enter_Status(CHECK_CONDITION);
}
else if (command == 0x17) // release
{
if ((scsiDev.reservedId < 0) || canRelease)
{
scsiDev.reservedId = -1;
scsiDev.reserverId = -1;
}
else
{
enter_Status(CONFLICT);
}
}
else // assume reserve.
{
if ((scsiDev.reservedId < 0) || canRelease)
{
scsiDev.reserverId = scsiDev.initiatorId;
if (thirdPty)
{
scsiDev.reservedId = thirdPtyId;
}
else
{
scsiDev.reservedId = scsiDev.initiatorId;
}
}
else
{
// Already reserved by someone else!
enter_Status(CONFLICT);
}
}
}
static void scsiReset()
{
scsiDev.rstCount++;
ledOff();
scsiPhyReset();
SCSI_Out_Ctl_Write(0);
scsiDev.parityError = 0;
scsiDev.phase = BUS_FREE;
scsiDev.atnFlag = 0;
scsiDev.resetFlag = 0;
scsiDev.lun = -1;
if (scsiDev.unitAttention != POWER_ON_RESET)
{
scsiDev.unitAttention = SCSI_BUS_RESET;
}
scsiDev.reservedId = -1;
scsiDev.reserverId = -1;
scsiDev.sense.code = NO_SENSE;
scsiDev.sense.asc = NO_ADDITIONAL_SENSE_INFORMATION;
scsiDiskReset();
scsiDev.postDataOutHook = NULL;
// Sleep to allow the bus to settle down a bit.
// We must be ready again within the "Reset to selection time" of
// 250ms.
// There is no guarantee that the RST line will be negated by then.
// NOTE: We could be connected and powered by USB for configuration,
// in which case TERMPWR cannot be supplied, and reset will ALWAYS
// be true.
CyDelay(10); // 10ms.
}
static void enter_SelectionPhase()
{
// Ignore stale versions of this flag, but ensure we know the
// current value if the flag is still set.
scsiDev.atnFlag = 0;
scsiDev.parityError = 0;
scsiDev.dataPtr = 0;
scsiDev.savedDataPtr = 0;
scsiDev.dataLen = 0;
scsiDev.status = GOOD;
scsiDev.phase = SELECTION;
scsiDev.lun = -1;
transfer.blocks = 0;
transfer.currentBlock = 0;
scsiDev.postDataOutHook = NULL;
}
static void process_SelectionPhase()
{
int sel = SCSI_ReadPin(SCSI_In_SEL);
int bsy = SCSI_ReadPin(SCSI_In_BSY);
// Only read these pins AFTER SEL and BSY - we don't want to catch them
// during a transition period.
uint8 mask = scsiReadDBxPins();
int maskBitCount = countBits(mask);
int goodParity = (Lookup_OddParity[mask] == SCSI_ReadPin(SCSI_In_DBP));
if (!bsy && sel &&
(mask & scsiDev.scsiIdMask) &&
(goodParity || !config->enableParity) && (maskBitCount <= 2))
{
// Do we enter MESSAGE OUT immediately ? SCSI 1 and 2 standards says
// move to MESSAGE OUT if ATN is true before we assert BSY.
// The initiator should assert ATN with SEL.
scsiDev.atnFlag = SCSI_ReadPin(SCSI_ATN_INT);
// Unit attention breaks many older SCSI hosts. Disable it completely for
// SCSI-1 (and older) hosts, regardless of our configured setting.
if (!scsiDev.atnFlag)
{
scsiDev.unitAttention = 0;
}
// We've been selected!
// Assert BSY - Selection success!
// must happen within 200us (Selection abort time) of seeing our
// ID + SEL.
// (Note: the initiator will be waiting the "Selection time-out delay"
// for our BSY response, which is actually a very generous 250ms)
SCSI_SetPin(SCSI_Out_BSY);
ledOn();
scsiDev.selCount++;
// Wait until the end of the selection phase.
while (!scsiDev.resetFlag)
{
if (!SCSI_ReadPin(SCSI_In_SEL))
{
break;
}
}
// Save our initiator now that we're no longer in a time-critical
// section.
// SCSI1/SASI initiators may not set their own ID.
if (maskBitCount == 2)
{
int i;
uint8 initiatorMask = mask ^ scsiDev.scsiIdMask;
scsiDev.initiatorId = 0;
for (i = 0; i < 8; ++i)
{
if (initiatorMask & (1 << i))
{
scsiDev.initiatorId = i;
break;
}
}
}
else
{
scsiDev.initiatorId = -1;
}
scsiDev.phase = COMMAND;
}
else if (!sel)
{
scsiDev.phase = BUS_BUSY;
}
}
static void process_MessageOut()
{
scsiEnterPhase(MESSAGE_OUT);
scsiDev.atnFlag = 0;
scsiDev.parityError = 0;
scsiDev.msgOut = scsiReadByte();
scsiDev.msgCount++;
if (scsiDev.parityError)
{
// Skip the remaining message bytes, and then start the MESSAGE_OUT
// phase again from the start. The initiator will re-send the
// same set of messages.
while (SCSI_ReadPin(SCSI_ATN_INT) && !scsiDev.resetFlag)
{
scsiReadByte();
}
// Go-back and try the message again.
scsiDev.atnFlag = 1;
scsiDev.parityError = 0;
}
else if (scsiDev.msgOut == 0x00)
{
// COMMAND COMPLETE. but why would the target be receiving this ? nfi.
enter_BusFree();
}
else if (scsiDev.msgOut == 0x06)
{
// ABORT
scsiDiskReset();
enter_BusFree();
}
else if (scsiDev.msgOut == 0x0C)
{
// BUS DEVICE RESET
scsiDiskReset();
scsiDev.unitAttention = SCSI_BUS_RESET;
// ANY initiator can reset the reservation state via this message.
scsiDev.reservedId = -1;
scsiDev.reserverId = -1;
enter_BusFree();
}
else if (scsiDev.msgOut == 0x05)
{
// Initiate Detected Error
// Ignore for now
}
else if (scsiDev.msgOut == 0x0F)
{
// INITIATE RECOVERY
// Ignore for now
}
else if (scsiDev.msgOut == 0x10)
{
// RELEASE RECOVERY
// Ignore for now
enter_BusFree();
}
else if (scsiDev.msgOut == MSG_REJECT)
{
// Message Reject
// Oh well.
scsiDev.resetFlag = 1;
}
else if (scsiDev.msgOut == 0x08)
{
// NOP
}
else if (scsiDev.msgOut == 0x09)
{
// Message Parity Error
// Go back and re-send the last message.
scsiDev.phase = MESSAGE_IN;
}
else if (scsiDev.msgOut & 0x80) // 0x80 -> 0xFF
{
// IDENTIFY
// We don't disconnect, so ignore disconnect privilege.
if ((scsiDev.msgOut & 0x18) || // Reserved bits set.
(scsiDev.msgOut & 0x20)) // We don't have any target routines!
{
messageReject();
}
scsiDev.lun = scsiDev.msgOut & 0x7;
//scsiDev.allowDisconnect = scsiDev.msgOut & 0x40;
}
else if (scsiDev.msgOut >= 0x20 && scsiDev.msgOut <= 0x2F)
{
// Two byte message. We don't support these. read and discard.
scsiReadByte();
}
else if (scsiDev.msgOut == 0x01)
{
int i;
// Extended message.
int msgLen = scsiReadByte();
if (msgLen == 0) msgLen = 256;
for (i = 0; i < msgLen && !scsiDev.resetFlag; ++i)
{
// Discard bytes.
scsiReadByte();
}
// We don't support ANY extended messages.
// Modify Data Pointer: We don't support reselection.
// Wide Data Transfer Request: No. 8bit only.
// Synchronous data transfer request. No, we can't do that.
// We don't support any 2-byte messages either.
// And we don't support any optional 1-byte messages.
// In each case, the correct response is MESSAGE REJECT.
messageReject();
}
else
{
messageReject();
}
// Re-check the ATN flag in case it stays asserted.
scsiDev.atnFlag |= SCSI_ReadPin(SCSI_ATN_INT);
}
void scsiPoll(void)
{
if (scsiDev.resetFlag)
{
scsiReset();
if ((scsiDev.resetFlag = SCSI_ReadPin(SCSI_RST_INT)))
{
// Still in reset phase. Do not try and process any commands.
return;
}
}
switch (scsiDev.phase)
{
case BUS_FREE:
if (SCSI_ReadPin(SCSI_In_BSY))
{
scsiDev.phase = BUS_BUSY;
}
// The Arbitration phase is optional for SCSI1/SASI hosts if there is only
// one initiator in the chain. Support this by moving
// straight to selection if SEL is asserted.
// ie. the initiator won't assert BSY and it's own ID before moving to selection.
else if (SCSI_ReadPin(SCSI_In_SEL))
{
enter_SelectionPhase();
}
break;
case BUS_BUSY:
// Someone is using the bus. Perhaps they are trying to
// select us.
if (SCSI_ReadPin(SCSI_In_SEL))
{
enter_SelectionPhase();
}
else if (!SCSI_ReadPin(SCSI_In_BSY))
{
scsiDev.phase = BUS_FREE;
}
break;
case ARBITRATION:
// TODO Support reselection.
break;
case SELECTION:
process_SelectionPhase();
break;
case RESELECTION:
// Not currently supported!
break;
case COMMAND:
// Do not check ATN here. SCSI 1 & 2 initiators must set ATN
// and SEL together upon entering the selection phase if they
// want to send a message (IDENTIFY) immediately.
if (scsiDev.atnFlag)
{
process_MessageOut();
}
else
{
process_Command();
}
break;
case DATA_IN:
scsiDev.atnFlag |= SCSI_ReadPin(SCSI_ATN_INT);
if (scsiDev.atnFlag)
{
process_MessageOut();
}
else
{
process_DataIn();
}
break;
case DATA_OUT:
scsiDev.atnFlag |= SCSI_ReadPin(SCSI_ATN_INT);
if (scsiDev.atnFlag)
{
process_MessageOut();
}
else
{
process_DataOut();
}
break;
case STATUS:
scsiDev.atnFlag |= SCSI_ReadPin(SCSI_ATN_INT);
if (scsiDev.atnFlag)
{
process_MessageOut();
}
else
{
process_Status();
}
break;
case MESSAGE_IN:
scsiDev.atnFlag |= SCSI_ReadPin(SCSI_ATN_INT);
if (scsiDev.atnFlag)
{
process_MessageOut();
}
else
{
process_MessageIn();
}
break;
case MESSAGE_OUT:
process_MessageOut();
break;
}
}
void scsiInit()
{
scsiDev.scsiIdMask = 1 << (config->scsiId);
scsiDev.atnFlag = 0;
scsiDev.resetFlag = 1;
scsiDev.phase = BUS_FREE;
scsiDev.reservedId = -1;
scsiDev.reserverId = -1;
scsiDev.unitAttention = POWER_ON_RESET;
}
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