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Annotation of driverkit/notes/enetErrors, revision 1.1

1.1     ! root        1:                        Ethernet error handling
        !             2:                        
        !             3: Transmit errors
        !             4: 
        !             5: * All errors: we don't know which buffer caused error, due to the design 
        !             6:   of the TE. In all cases we have to dequeue everything and throw them 
        !             7:   all away.
        !             8:   
        !             9: * channel errorInterrupt, busError
        !            10:   -- action:
        !            11:        reset, dequeue and discard all frames
        !            12:         
        !            13:   << the rest of these are in etxAddlInt_t >>
        !            14:   
        !            15: * Late collision
        !            16:   -- Disables channel
        !            17:   -- action:
        !            18:        reset, dequeue and discard all frames
        !            19:   
        !            20: * underrun
        !            21:   -- Disables channel
        !            22:   -- action:
        !            23:        reset, dequeue and discard all frames
        !            24:        
        !            25: * No Heart beat
        !            26:   -- Only useful for TPE; mask off for thin wire
        !            27:   -- Channel not disabled
        !            28:   -- action:
        !            29:        reset, dequeue and discard all frames;
        !            30:         enJam();
        !            31:        
        !            32: * > 15 retries
        !            33:   -- Disables channel
        !            34:   -- action:
        !            35:        reset, dequeue and discard all frames;
        !            36:         enJam();
        !            37:                
        !            38: Receive errors
        !            39: 
        !            40: * descriptor chan_status errors
        !            41:   * short packet - should never happen
        !            42:   * alignment error
        !            43:   * CRC error 
        !            44:   * collided packet
        !            45:   -- Action:
        !            46:        drop packet on floor.
        !            47:        
        !            48: * channel errorInterrupt, busError
        !            49:   -- Disables channel (maybe...)
        !            50:   -- action:
        !            51:        dmaAbort (to be sure);
        !            52:        dequeue completed frames and restart;
        !            53:        
        !            54: * overrun
        !            55:   -- Disables channel
        !            56:   -- action:
        !            57:        dequeue completed frames and restart;
        !            58:        
        !            59: * CRC error - mask this interrupt; detected in descriptor chan_status
        !            60: 
        !            61: * Alignment error - mask this interrupt; detected in descriptor user status
        !            62: 
        !            63: Net Jammed errors
        !            64: 
        !            65: * detected:
        !            66:   -- > 15 retries, s/w retry count exceeded
        !            67:   -- No heart beat, s/w retry count exceeded
        !            68:   -- timeout on TX interrupt 
        !            69:   
        !            70: * Action:
        !            71:   
        !            72: m68k en_jam() {
        !            73:        if TPE selected {
        !            74:                if link integrity OK
        !            75:                        return good;
        !            76:                else {
        !            77:                        select Thin wire;
        !            78:                        enable LoopBack (??);
        !            79:                        return error;
        !            80:                }
        !            81:                        
        !            82:        }
        !            83:        else (thin wire selected) {     
        !            84:                if link integrity of TPE OK {
        !            85:                        select TPE;
        !            86:                        Enable loopback (??);
        !            87:                        return GOOD;
        !            88:                }
        !            89:                else {
        !            90:                        log "Net Jammed" message if we haven't already done so;
        !            91:                        set ENF_JAMMED flag;
        !            92:                        if_down();
        !            93:                        timeout(antijam); // clears ENF_JAMMED flag after 10 
        !            94:                                          //   seconds
        !            95:                        return error;
        !            96:                }
        !            97:        }
        !            98: }
        !            99:   
        !           100: m88k enJam() {
        !           101: 
        !           102:        if (++retry_count < max) 
        !           103:                return good;
        !           104: 
        !           105:        remember current I/F mode (TPE or thin);
        !           106:        select TPE;
        !           107:        wait some h/w delay for Link Integrity to settle down;
        !           108:        if link integrity good {
        !           109:                return good;
        !           110:        }
        !           111:        else if (mode was TPE on entry) {
        !           112:                select Thin wire;
        !           113:                return good;
        !           114:        }
        !           115:        
        !           116:        /* 
        !           117:         * Net down.
        !           118:         */
        !           119:        dequeue and free all frames;
        !           120:        set net_down flag; set timeout to clear it in 10 seconds;
        !           121:        if_down();
        !           122:        return bad;
        !           123: }

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