-- EthernetHeadD0.mesa (last edited by: HGM on: September 14, 1980  6:33 AM)

DIRECTORY
  Inline USING [LowHalf],
  HeadStartChain USING [Start],
  DeviceCleanup USING [Item, Await],
  D0InputOutput USING [
    CSB, IOPage, ethernetIn, ethernetOut,
    ControllerNumber, GetNextController, nullControllerNumber],
  Mopcodes USING [zMISC, zSTARTIO],
  SpecialSystem USING [ProcessorID],
  EthernetFace;

EthernetHeadD0: PROGRAM
  IMPORTS D0InputOutput, DeviceCleanup, RemainingStartChain: HeadStartChain, Inline
  EXPORTS EthernetFace, HeadStartChain =
BEGIN OPEN EthernetFace;

-- These are the data structures that the microcode knows about.  If some other module (for example, a diagnostic) ever needs this info, it should probably get split out into a separate module.  For now, it is lumped in here to avoid cluttering up the world with yet another file.

OCSB: TYPE = LONG POINTER TO OutputControllerStatusBlock;
OutputControllerStatusBlock: TYPE = MACHINE DEPENDENT RECORD [ 
  next: ShortIOCB,
  unused1: WORD,
  unused2: WORD,
  unused3: WORD,
  interruptBit: WORD, -- words after here are unused by microcode
  last: IOCB ]; -- last IOCB on output queue, valid if next#noIOCB

ICSB: TYPE = LONG POINTER TO InputControllerStatusBlock;
InputControllerStatusBlock: TYPE = MACHINE DEPENDENT RECORD [ 
  next: ShortIOCB,
  host: SpecialSystem.ProcessorID,
  interruptBit: WORD,
  missed: WORD,  -- for debugging only
  spare1: WORD,
  spare2: WORD,
  buffer: ARRAY [0..4) OF CARDINAL, -- words after here are unused by microcode
  last: IOCB ]; -- last IOCB on input queue, valid if next#noIOCB

IOCB: TYPE = LONG POINTER TO IOControlBlock;
-- Beware that you don't automatically lengthen one of these.  If you do you will end up with a pointer into your MDS rather then the first 64K where the IOCBs live.  That won't work unless your MDS is also the first 64K.
ShortIOCB: TYPE = POINTER TO IOControlBlock;
IOControlBlock: TYPE = MACHINE DEPENDENT RECORD [
  next: ShortIOCB,
  mask: WORD,
  spare: WORD,
  completion: WORD,
  used: CARDINAL,  -- input only
  length: CARDINAL,
  buffer: LONG POINTER ];  -- NB: Must be QuadWord Aligned

StartIO: PROCEDURE [SioParameter] =
    MACHINE CODE BEGIN Mopcodes.zSTARTIO END;

SioParameter: TYPE = RECORD [WORD];
  firstFixupOutput: SioParameter = [20B];
  firstFixupInput: SioParameter = [40B];
  firstReset: SioParameter = [60B];
  secondFixupOutput: SioParameter = [100B];
  secondFixupInput: SioParameter = [200B];
  secondReset: SioParameter = [300B];

-- Input from reg 0 is device id

Output: PROCEDURE [Command, Register] =
    MACHINE CODE BEGIN Mopcodes.zMISC, 6; END;
Input: PROCEDURE [Register] RETURNS [WORD] =
    MACHINE CODE BEGIN Mopcodes.zMISC, 5; END;

Command: TYPE = RECORD [WORD];
  enableInput: Command = [220B];
  enableOutput: Command = [103B];

Register: TYPE = MACHINE DEPENDENT RECORD [
  zero: [0..377B] _ 0,
  controller: D0InputOutput.ControllerNumber,
  register: [0..17B]];

-- completion bits
processed: WORD = 040000B;
error: WORD = 020000B;
hardwareError: WORD = 010000B;
fragment, tooLong: WORD = 004000B;
loadOverflow: WORD = 002000B;
nothingYet: WORD = 0;
-- 001000 and 000400 are unused so far

-- Hardware error bits:
-- 001: Memory Data Fault (OFault)
-- 002: Collision
-- 004: Output Underrrun
-- 010: Bad Parity (between mem and shifter)
-- 020: CRC
-- 040: Jam
-- 100: Input Overrun
-- 200: Bad Alignment

noIOCB: ShortIOCB = LOOPHOLE[0];

Device: TYPE = RECORD [
  board: Board,
  in, out: D0InputOutput.ControllerNumber];

Board: TYPE = [0..2);

ICSBFronDevice: PROCEDURE [device: Device] RETURNS [ICSB] = INLINE
  BEGIN
  RETURN[LOOPHOLE[@D0InputOutput.IOPage[device.in]]];
  END;

OCSBFronDevice: PROCEDURE [device: Device] RETURNS [OCSB] = INLINE
  BEGIN
  RETURN[LOOPHOLE[@D0InputOutput.IOPage[device.out]]];
  END;

ControlRegister: PROCEDURE [c: D0InputOutput.ControllerNumber] RETURNS [Register] = INLINE
  BEGIN
  RETURN[[0,c,0]];  -- Register 0 is the control register
  END;

Shorten: PROCEDURE [iocb: IOCB] RETURNS [ShortIOCB] = INLINE
  BEGIN
  -- Maybe we should check to be sure that the high half is zero
  RETURN[Inline.LowHalf[iocb]];
  END;


-- EXPORTed TYPEs
DeviceHandle: PUBLIC TYPE = Device;
ControlBlockRecord: PUBLIC TYPE = IOControlBlock;

-- EXPORTed variables

nullDeviceHandle: PUBLIC DeviceHandle _ LOOPHOLE[123456B];
globalStateSize: PUBLIC CARDINAL _ 0;
controlBlockSize: PUBLIC CARDINAL _ SIZE[IOControlBlock];
hearSelf: PUBLIC BOOLEAN _ TRUE;


-- Non EXPORTed things.  Note that all the state information lives in the CSBs.
 
fixupInputBits: ARRAY Board OF SioParameter = [firstFixupInput, secondFixupInput];
fixupOutputBits: ARRAY Board OF SioParameter = [firstFixupOutput, secondFixupOutput];
resetBits: ARRAY Board OF SioParameter = [firstReset, secondReset];

QueueOutput: PUBLIC PROCEDURE [
  device: Device, buffer: LONG POINTER, length: CARDINAL, cb: IOCB] =
  BEGIN
  out: OCSB = OCSBFronDevice[device];
  cb^ _ [
    next: noIOCB,
    mask: 0,
    spare: 0,
    completion: 0,
    used: 0,
    length: length,
    buffer: buffer ];
  IF out.next=noIOCB THEN
    BEGIN  -- new iocb, hardware idle
    out.next _ Shorten[cb];
    Output[enableOutput,ControlRegister[device.out]];  -- poke hardware
    END
  ELSE
    BEGIN  -- output active, add to end of chain
    out.last.next _ Shorten[cb];
    IF out.next=noIOCB AND cb.completion=0 THEN
      BEGIN  -- oops, hardware went idle
      out.next _ Shorten[cb];
      Output[enableOutput,ControlRegister[device.out]];  -- poke hardware
      END;
    END;
  out.last _ cb;
  END;

QueueInput: PUBLIC PROCEDURE [
    device: Device, buffer: LONG POINTER, length: CARDINAL, cb: IOCB] =
  BEGIN
  in: ICSB = ICSBFronDevice[device];
  cb^ _ [
    next: noIOCB,
    mask: 0,
    spare: 0,
    completion: 0,
    used: 0,
    length: length,
    buffer: buffer ];
  IF in.next#noIOCB THEN in.last.next _ Shorten[cb];
  IF in.next=noIOCB AND cb.completion=0 THEN
    BEGIN
    in.next _ Shorten[cb];
    Output[enableInput,ControlRegister[device.in]];
    END;
  in.last _ cb;
  END;

GetStatus: PUBLIC PROCEDURE [cb: IOCB] RETURNS [status: Status] =
  BEGIN
  RETURN [
    SELECT cb.completion FROM
      0 => pending,
      40000B => ok,
      62000B => tooManyCollisions,
      61000B => packetTooLong,
      70200B => badAlignmentButOkCrc,
      70020B => crc,
      70220B => crcAndBadAlignment,
      70100B, 70120B, 70300B, 70320B => overrun,
      70004B, 70006B => underrun,
      ENDCASE => otherError ];
  END;

GetRetries: PUBLIC PROCEDURE [cb: IOCB] RETURNS [CARDINAL] =
  BEGIN
  RETURN [
    SELECT cb.mask FROM
      1 => 0,
      3 => 1,
      7 => 2,
      17B => 3,
      37B => 4,
      77B => 5,
      177B => 6,
      377B => 7,
      777B => 8,
      1777B => 9,
      3777B => 10,
      7777B => 11,
      17777B => 12,
      37777B => 13,
      77777B => 14,
      177777B => 15,
      ENDCASE => 16 ];
  END;

GetPacketLength: PUBLIC PROCEDURE [cb: IOCB] RETURNS [CARDINAL] =
  BEGIN
  RETURN [cb.used];
  END;

GetPacketsMissed: PUBLIC PROCEDURE [device: Device] RETURNS [CARDINAL] =
  BEGIN
  RETURN [ICSBFronDevice[device].missed];
  END;

GetNextDevice: PUBLIC PROCEDURE [device: Device] RETURNS [Device] =
  BEGIN OPEN D0InputOutput;
  IF device=nullDeviceHandle THEN
    device _ [0,nullControllerNumber,nullControllerNumber]
  ELSE device.board _ device.board + 1;
  device.in _ GetNextController[ethernetIn,device.in];
  device.out _ GetNextController[ethernetOut,device.out];
  IF device.in=nullControllerNumber OR device.out=nullControllerNumber THEN
    RETURN[nullDeviceHandle];
  RETURN[device];
  END;

TurnOn: PUBLIC PROCEDURE [
    device: Device,
    host: SpecialSystem.ProcessorID,
    inInterrupt, outInterrupt: WORD,
    globalState: GlobalStatePtr] =
  BEGIN
  board: Board = device.board;
  out: OCSB = OCSBFronDevice[device];
  in: ICSB = ICSBFronDevice[device];
  StartIO[resetBits[board]];
  out^ _ [
    next: noIOCB,
    unused1: 0,
    unused2: 0,
    unused3: 0,
    interruptBit: outInterrupt,
    last: NIL ];
  in^ _ [
    next: noIOCB,
    host: host,
    interruptBit: inInterrupt,
    missed: 0,
    spare1: 0,
    spare2: 0,
    buffer: [0,0,0,0],
    last: NIL ];
  StartIO[fixupInputBits[board]];
  StartIO[fixupOutputBits[board]];
  Output[enableInput,ControlRegister[device.in]];
  END;

TurnOff: PUBLIC PROCEDURE [device: Device] =
  BEGIN
  StartIO[resetBits[device.board]];
  END;

-- There is no way to remove a cleanup procedure yet, so we have a flag to avoid duplicates.
alreadyInitializedCleanup: ARRAY Board OF BOOLEAN _ ALL[FALSE];

savedICSB: InputControllerStatusBlock;
savedOCSB: OutputControllerStatusBlock;

AddCleanup: PUBLIC PROCEDURE [device: Device] =
  BEGIN OPEN DeviceCleanup;
  item: Item;
  board: Board = device.board;
  out: OCSB = OCSBFronDevice[device];
  in: ICSB = ICSBFronDevice[device];
  oldHost: SpecialSystem.ProcessorID;
  IF alreadyInitializedCleanup[device.board] THEN RETURN;
  alreadyInitializedCleanup[device.board] _ TRUE;
  DO
    SELECT Await[@item] FROM
      kill =>
        BEGIN
        StartIO[resetBits[board]];
        END;
      turnOff =>
        BEGIN
        StartIO[resetBits[board]];
        savedICSB _ in^;
        savedOCSB _ out^;
        oldHost _ in.host;
        END;
      turnOn =>
        BEGIN
-- Note that this does NOT really put things back together.  It simply smashes things to a safe state.  The intention is that the driver will notice that nothing is happening and then call TurnOff+TurnOn to reset things.  That allows Pilot to reset the GMT clock on the way back from the debugger without getting tangled up with the normal Ethernet driver.
        StartIO[resetBits[board]];
        out^ _ [
          next: noIOCB,
          unused1: 0,
          unused2: 0,
          unused3: 0,
          interruptBit: 0,
          last: NIL ];
        in^ _ [
          next: noIOCB,
          host: oldHost,  -- Ugh, it would be nice if we could do something better
          interruptBit: 0,
          missed: 0,
          spare1: 0,
          spare2: 0,
          buffer: [0,0,0,0],
          last: NIL ];
        StartIO[fixupInputBits[board]];
        StartIO[fixupOutputBits[board]];
        Output[enableInput,ControlRegister[device.in]];
        END;
      ENDCASE;
    ENDLOOP;
  END;

RemoveCleanup: PUBLIC PROCEDURE [device: Device] = BEGIN END;

-- Other routines to keep the rest of the world happy

Start: PUBLIC PROCEDURE =
  BEGIN  -- Start this module (and rest of chain)
  RemainingStartChain.Start[]
  END;

END.  -- EthernetHeadD0.

LOG
Time: September 4, 1980  11:02 PM By: HGM, Action: create file. 
Time: September 14, 1980  6:33 AM By: HGM, Action: buffer overflow bug. 
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