Implement a state machine clock that acutally limits how fast

the nsgige state machine can run. The frequency is of the actual
state transitions, and not the rate of what underlying
instructions might run at.

dev/ns_gige.cc:
    Implement a state machine clock that acutally limits how fast
    the state machine can run.  After each state transition, a
    variable is kept to hold the next state transition until the
    next clock.  The frequency is of the actual state transitions,
    and not the rate of what underlying instructions might run at.
dev/ns_gige.hh:
    Add back the rxKickEvent and txKickEvent events.
python/m5/objects/Ethernet.py:
    Default the state machine clock to '0ns' so the default
    behaviour doesn't change when we actually implement the
    state machine clock.

--HG--
extra : convert_revision : 2db1943dee4e91ea75aaee6a91e88f27f01a09dd

dev/ns_gige.cc

@@ -102,7 +102,7 @@ NSGigE::NSGigE(Params *p)
       txDmaReadEvent(this), txDmaWriteEvent(this),
       dmaDescFree(p->dma_desc_free), dmaDataFree(p->dma_data_free),
       txDelay(p->tx_delay), rxDelay(p->rx_delay),
-      rxKickTick(0), txKickTick(0),
+      rxKickTick(0), rxKickEvent(this), txKickTick(0), txKickEvent(this),
       txEvent(this), rxFilterEnable(p->rx_filter), acceptBroadcast(false),
       acceptMulticast(false), acceptUnicast(false),
       acceptPerfect(false), acceptArp(false),
@@ -841,7 +841,8 @@ NSGigE::write(MemReqPtr &req, const uint8_t *data)
                 panic("writing to read-only or reserved CFGR bits!\n");
 
             regs.config |= reg & ~(CFGR_LNKSTS | CFGR_SPDSTS | CFGR_DUPSTS |
-                                   CFGR_RESERVED | CFGR_T64ADDR | CFGR_PCI64_DET);
+                                   CFGR_RESERVED | CFGR_T64ADDR |
+                                   CFGR_PCI64_DET);
 
 // all these #if 0's are because i don't THINK the kernel needs to
 // have these implemented. if there is a problem relating to one of
@@ -1487,13 +1488,19 @@ NSGigE::rxKick()
     DPRINTF(EthernetSM, "receive kick rxState=%s (rxBuf.size=%d)\n",
             NsRxStateStrings[rxState], rxFifo.size());
 
+  next:
+    if (clock) {
         if (rxKickTick > curTick) {
             DPRINTF(EthernetSM, "receive kick exiting, can't run till %d\n",
                     rxKickTick);
-        return;
+
+            goto exit;
+        }
+
+        // Go to the next state machine clock tick.
+        rxKickTick = curTick + cycles(1);
     }
 
-  next:
     switch(rxDmaState) {
       case dmaReadWaiting:
         if (doRxDmaRead())
@@ -1561,8 +1568,7 @@ NSGigE::rxKick()
         if (rxDmaState != dmaIdle)
             goto exit;
 
-        DPRINTF(EthernetDesc,
+        DPRINTF(EthernetDesc, "rxDescCache: addr=%08x read descriptor\n",
-                "rxDescCache: addr=%08x read descriptor\n",
                 regs.rxdp & 0x3fffffff);
         DPRINTF(EthernetDesc,
                 "rxDescCache: link=%08x bufptr=%08x cmdsts=%08x extsts=%08x\n",
@@ -1783,7 +1789,6 @@ NSGigE::rxKick()
 
     DPRINTF(EthernetSM, "entering next rxState=%s\n",
             NsRxStateStrings[rxState]);
-
     goto next;
 
   exit:
@@ -1792,6 +1797,9 @@ NSGigE::rxKick()
      */
     DPRINTF(EthernetSM, "rx state machine exited rxState=%s\n",
             NsRxStateStrings[rxState]);
+
+    if (clock && !rxKickEvent.scheduled())
+        rxKickEvent.schedule(rxKickTick);
 }
 
 void
@@ -1954,13 +1962,18 @@ NSGigE::txKick()
     DPRINTF(EthernetSM, "transmit kick txState=%s\n",
             NsTxStateStrings[txState]);
 
+  next:
+    if (clock) {
         if (txKickTick > curTick) {
             DPRINTF(EthernetSM, "transmit kick exiting, can't run till %d\n",
                     txKickTick);
-        return;
+            goto exit;
+        }
+
+        // Go to the next state machine clock tick.
+        txKickTick = curTick + cycles(1);
     }
 
-  next:
     switch(txDmaState) {
       case dmaReadWaiting:
         if (doTxDmaRead())
@@ -2022,6 +2035,8 @@ NSGigE::txKick()
         if (txDmaState != dmaIdle)
             goto exit;
 
+        DPRINTF(EthernetDesc, "txDescCache: addr=%08x read descriptor\n",
+                regs.txdp & 0x3fffffff);
         DPRINTF(EthernetDesc,
                 "txDescCache: link=%08x bufptr=%08x cmdsts=%08x extsts=%08x\n",
                 txDescCache.link, txDescCache.bufptr, txDescCache.cmdsts,
@@ -2186,6 +2201,11 @@ NSGigE::txKick()
         if (txDescCache.cmdsts & CMDSTS_INTR)
             devIntrPost(ISR_TXDESC);
 
+        if (!txEnable) {
+            DPRINTF(EthernetSM, "halting TX state machine\n");
+            txState = txIdle;
+            goto exit;
+        } else
             txState = txAdvance;
         break;
 
@@ -2215,7 +2235,6 @@ NSGigE::txKick()
 
     DPRINTF(EthernetSM, "entering next txState=%s\n",
             NsTxStateStrings[txState]);
-
     goto next;
 
   exit:
@@ -2224,6 +2243,9 @@ NSGigE::txKick()
      */
     DPRINTF(EthernetSM, "tx state machine exited txState=%s\n",
             NsTxStateStrings[txState]);
+
+    if (clock && !txKickEvent.scheduled())
+        txKickEvent.schedule(txKickTick);
 }
 
 void
@@ -2429,6 +2451,7 @@ NSGigE::serialize(ostream &os)
     SERIALIZE_SCALAR(rxDescCache.bufptr);
     SERIALIZE_SCALAR(rxDescCache.cmdsts);
     SERIALIZE_SCALAR(rxDescCache.extsts);
+    SERIALIZE_SCALAR(extstsEnable);
 
     /*
      * Serialize tx state machine
@@ -2441,6 +2464,7 @@ NSGigE::serialize(ostream &os)
     SERIALIZE_SCALAR(txDescCnt);
     int txDmaState = this->txDmaState;
     SERIALIZE_SCALAR(txDmaState);
+    SERIALIZE_SCALAR(txKickTick);
 
     /*
      * Serialize rx state machine
@@ -2454,8 +2478,7 @@ NSGigE::serialize(ostream &os)
     SERIALIZE_SCALAR(rxDescCnt);
     int rxDmaState = this->rxDmaState;
     SERIALIZE_SCALAR(rxDmaState);
-
+    SERIALIZE_SCALAR(rxKickTick);
-    SERIALIZE_SCALAR(extstsEnable);
 
     /*
      * If there's a pending transmit, store the time so we can
@@ -2575,6 +2598,7 @@ NSGigE::unserialize(Checkpoint *cp, const std::string &section)
     UNSERIALIZE_SCALAR(rxDescCache.bufptr);
     UNSERIALIZE_SCALAR(rxDescCache.cmdsts);
     UNSERIALIZE_SCALAR(rxDescCache.extsts);
+    UNSERIALIZE_SCALAR(extstsEnable);
 
     /*
      * unserialize tx state machine
@@ -2589,6 +2613,9 @@ NSGigE::unserialize(Checkpoint *cp, const std::string &section)
     int txDmaState;
     UNSERIALIZE_SCALAR(txDmaState);
     this->txDmaState = (DmaState) txDmaState;
+    UNSERIALIZE_SCALAR(txKickTick);
+    if (txKickTick)
+        txKickEvent.schedule(txKickTick);
 
     /*
      * unserialize rx state machine
@@ -2604,8 +2631,9 @@ NSGigE::unserialize(Checkpoint *cp, const std::string &section)
     int rxDmaState;
     UNSERIALIZE_SCALAR(rxDmaState);
     this->rxDmaState = (DmaState) rxDmaState;
-
+    UNSERIALIZE_SCALAR(rxKickTick);
-    UNSERIALIZE_SCALAR(extstsEnable);
+    if (rxKickTick)
+        rxKickEvent.schedule(rxKickTick);
 
      /*
      * If there's a pending transmit, reschedule it now

dev/ns_gige.hh

@@ -266,11 +266,13 @@ class NSGigE : public PciDev
     Tick rxKickTick;
     typedef EventWrapper<NSGigE, &NSGigE::rxKick> RxKickEvent;
     friend void RxKickEvent::process();
+    RxKickEvent rxKickEvent;
 
     void txKick();
     Tick txKickTick;
     typedef EventWrapper<NSGigE, &NSGigE::txKick> TxKickEvent;
     friend void TxKickEvent::process();
+    TxKickEvent txKickEvent;
 
     /**
      * Retransmit event

python/m5/objects/Ethernet.py

@@ -64,7 +64,7 @@ class NSGigE(PciDevice):
     hardware_address = Param.EthernetAddr(NextEthernetAddr,
         "Ethernet Hardware Address")
 
-    clock = Param.Clock('100MHz', "State machine processor frequency")
+    clock = Param.Clock('0ns', "State machine processor frequency")
 
     dma_data_free = Param.Bool(False, "DMA of Data is free")
     dma_desc_free = Param.Bool(False, "DMA of Descriptors is free")