sims/e1000_gem5: fix clock edges consistent with e1000 in gem5

sims/nic/e1000_gem5/e1000_gem5.cc

@@ -78,6 +78,14 @@ void IGbE::Timed(nicbm::TimedEvent &te)
 /******************************************************************************/
 /* gem5-ish APIs */
 
+Tick IGbE::clockEdge(Tick t)
+{
+    if (t % 1000 != 0)
+        t += 1000 - (t % 1000);
+    t += 1000;
+    return t;
+}
+
 void IGbE::schedule(EventFunctionWrapper &ev, Tick t)
 {
     if (ev.sched) {

sims/nic/e1000_gem5/i8254xGBe.cc

@@ -1846,7 +1846,7 @@ IGbE::restartClock()
     DPRINTF(EthernetSM, "IGbE: requesting restart clock: sched=%d rxt=%d txt=%d txf=%d\n",
     tickEvent.scheduled(), rxTick, txTick, txFifoTick);
     if (!tickEvent.scheduled() && (rxTick || txTick || txFifoTick)) {
-        schedule(tickEvent, curTick() + 1000);
+        schedule(tickEvent, clockEdge(curTick()));
         DPRINTF(EthernetSM, "IGbE: scheduled\n");
     }
 }

sims/nic/e1000_gem5/i8254xGBe.h

@@ -71,6 +71,7 @@ class IGbE : public nicbm::Runner::Device
     virtual void Timed(nicbm::TimedEvent &te);
 
 
+    Tick clockEdge(Tick t);
     void schedule(EventFunctionWrapper &ev, Tick t);
     void reschedule(EventFunctionWrapper &ev, Tick t, bool always=false);
     void deschedule(EventFunctionWrapper &ev);
@@ -192,7 +193,7 @@ class IGbE : public nicbm::Runner::Device
      */
     void cpuClearInt();
 
-    Tick intClock() { return 1024 * 1024; /* 1us */ }
+    Tick intClock() { return 1000 * 1024; /* 1us */ }
 
     /** This function is used to restart the clock so it can handle things like
      * draining and resume in one place. */