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Annotation of kernel/bsd/dev/ppc/drvApple96_SCSI/StateMachines.m, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
        !             3:  *
        !             4:  * @APPLE_LICENSE_HEADER_START@
        !             5:  * 
        !             6:  * Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
        !             7:  * Reserved.  This file contains Original Code and/or Modifications of
        !             8:  * Original Code as defined in and that are subject to the Apple Public
        !             9:  * Source License Version 1.1 (the "License").  You may not use this file
        !            10:  * except in compliance with the License.  Please obtain a copy of the
        !            11:  * License at http://www.apple.com/publicsource and read it before using
        !            12:  * this file.
        !            13:  * 
        !            14:  * The Original Code and all software distributed under the License are
        !            15:  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
        !            16:  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
        !            17:  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
        !            18:  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
        !            19:  * License for the specific language governing rights and limitations
        !            20:  * under the License.
        !            21:  * 
        !            22:  * @APPLE_LICENSE_HEADER_END@
        !            23:  */
        !            24: 
        !            25: /**
        !            26:  * Copyright 1997 Apple Computer Inc. All Rights Reserved.
        !            27:  * @author     Martin Minow    mailto:[email protected]
        !            28:  * @revision   1997.02.12      Initial conversion from AMDPCSCSIDriver sources.
        !            29:  *
        !            30:  * There is no code in this module. It contains documentation of the 53C96 SCSI state
        !            31:  * machine.
        !            32:  *
        !            33:  * Note: we must use a comment here as some C compilers parse the text inside an #if 0
        !            34:  * and post errors if there are unbalanced quotes or similar.
        !            35:  */
        !            36: 
        !            37: /*
        !            38: 
        !            39: Primary Bus Operation State Machine
        !            40: 
        !            41: ** ** ** NOTE: This is slightly out of date. See the code for the actual logic. ** ** **
        !            42: 
        !            43: from                           to                                      where                   when
        !            44: -----------------      -----------------       --------------  -------------------------
        !            45: unknown                                SCS_UNINITIALIZED       -archInit               Initial probe
        !            46: xxx                                    SCS_DISCONNECTED        -hwReset                Any hardware reset
        !            47: xxx                                    SCS_DISCONNECTED        -hardwareInterrupt      iDisconnect interrupt
        !            48: -----------------
        !            49: SCS_DISCONNECTED       SCS_SELECTING           -hwStart                Start of select sequence
        !            50: SCS_DISCONNECTED       SCS_ACCEPTINGMSG        -fsmDisconnected Valid Reselect detected
        !            51: -----------------
        !            52: SCS_SELECTING          SCS_DISCONNECTED        -fsmSelecting   Select Timeout
        !            53: SCS_SELECTING          SCS_INITIATOR           -fsmSelecting   Select seq. interrupt (maybe incomplete)
        !            54: SCS_SELECTING          SCS_DISCONNECTED        -fsmSelecting   Reselect during select attempt
        !            55: -----------------
        !            56: SCS_INITIATOR          SCS_SENDINGCMD          -fsmPhaseChange Phase change to CMDO
        !            57: SCS_INITIATOR          SCS_COMPLETING          -fsmPhaseChange Phase change to STAT
        !            58: SCS_INITIATOR          SCS_GETTINGMSG          -fsmPhaseChange Phase change to MSGI
        !            59: SCS_INITIATOR          SCS_SENDINGMSG          -fsmPhaseChange Phase change to MSGO, msg bytes in FIFO
        !            60: SCS_INITIATOR          SCS_DMACOMPLETE                 -dmaStart               DMA setup in DATI/DATO phase
        !            61: -----------------
        !            62: SCS_SENDINGCMD         SCS_INITIATOR           -fsmSendingCmd  Good interrupt after sending cmd
        !            63: -----------------
        !            64: SCS_COMPLETING         SCS_ACCEPTINGMSG        -fsmCompleting  Good SCMD_INIT_CMD_CMPLT 
        !            65: SCS_COMPLETING         SCS_INITIATOR           -fsmCompleting  SCMD_INIT_CMD_CMPLT, but only STS byte.
        !            66: -----------------
        !            67: SCS_GETTINGMSG         SCS_ACCEPTINGMSG        -fsmGettingMsg  SCMD_MSG_ACCEPTED cmd sent
        !            68: -----------------
        !            69: SCS_ACCEPTINGMSG       SCS_GETTINGMSG          -fsmAcceptingMsg        Phase still MSGI
        !            70: SCS_ACCEPTINGMSG       SCS_INITIATOR           -fsmAcceptingMsg        Phase != MSGI
        !            71: SCS_ACCEPTINGMSG       SCS_DISCONNECTED        -fsmAcceptingMsg        Msg = Cmd complete
        !            72: SCS_ACCEPTINGMSG       SCS_DISCONNECTED        -fsmAcceptingMsg        Msg = disconnect
        !            73: SCS_ACCEPTINGMSG       SCS_INITIATOR           -fsmAcceptingMsg        Any other msg
        !            74: -----------------
        !            75: SCS_DMACOMPLETE                        SCS_INITIATOR           -fsmDMAComplete         DMA complete
        !            76: -----------------
        !            77: SCS_SENDINGMSG         SCS_INITIATOR           -fsmSendingMsg  Always
        !            78: 
        !            79: 
        !            80: Message Out State
        !            81: 
        !            82: The purpose of this is to provide a means to send a message out to the target. Basically,
        !            83: to do a message out:
        !            84: 
        !            85:   -- Set ATN true
        !            86:   -- Place message byte(s) in currMsgOut[]
        !            87:   -- Set currMsgOutCnt to length of message 
        !            88:   -- Set msgOutState = MOS_WAITING
        !            89: 
        !            90: All of these are done in -messageOut: for a single-byte message. For extended messages,
        !            91: context-specific code must perform these manually. 
        !            92: 
        !            93: When we see a phase change to message out, -fsmPhaseChange sends the message byte(s) from
        !            94: currMsgOut[] to the FIFO, does a SCMD_TRANSFER_INFO, and sets msgOutState to MOS_SAWMSGOUT.
        !            95: We go back to MOS_NONE when we see any other phase. 
        !            96: 
        !            97: from                           to                                      where                   when
        !            98: -----------------      -----------------       --------------  -------------------------
        !            99: xxx                                    MOS_NONE                        -hwReset                Hardware reset
        !           100: xxx                                    MOS_NONE                        -hwStart                Start of select sequence
        !           101: MOS_NONE                       MOS_WAITING                     -fsmSelecting   Select done, set ATN, sending SDTR msg
        !           102: MOS_NONE                       MOS_WAITING                     -fsmAcceptingMsg Target-init SDTR, we set ATN for our SDTR
        !           103: MOS_NONE                       MOS_WAITING                     -messageOut             Set ATN to do a single-byte msg out 
        !           104: MOS_WAITING                    MOS_SAWMSGOUT           -fsmPhaseChange Phase change to MSGO, our bytes in FIFO.
        !           105: MOS_SAWMSGOUT          MOS_NONE                        -fsmPhaseChange Phase != msg in or msg out
        !           106: 
        !           107: 
        !           108: This state machine keeps track of SDTR negotiations, both target- and host-initiated.
        !           109: 
        !           110: from                           to                                      where                   when
        !           111: -----------------      -----------------       --------------  -------------------------
        !           112: xxx                              SNS_NONE                              -hwReset                Hardware reset
        !           113: xxx                              SNS_HOST_INIT_NEEDED  -hwStart                We want to do SDTR 
        !           114: xxx                              SNS_NONE                              -hwStart                We don't want to do SDTR
        !           115: SNS_HOST_INIT_NEEDED   SNS_NONE                -fsmSelecting   No message phase after Sel complete
        !           116: SNS_HOST_INIT_NEEDED   SNS_HOST_INIT   -fsmPhaseChange Phase = MSGO after selection
        !           117: SNS_HOST_INIT          SNS_NONE                        -fsmAcceptingMsg Target rejected our SDTR.
        !           118: SNS_HOST_INIT          SNS_NONE                        -fsmAcceptingMsg Target's SDTR response recv'd
        !           119: SNS_HOST_INIT          SNS_NONE                        -fsmPhaseChange  No MSGIn after our SDTR sent.
        !           120: SNS_NONE                       SNS_TARGET_INIT         -fsmGettingMsg  Saw target-init'd SDTR
        !           121: SNS_TARGET_INIT          SNS_NONE                              -fsmSendingMsg  Completed target-init'd SDTR
        !           122: 
        !           123: */

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