Merge zizzer.eecs.umich.edu:/bk/newmem

into  zeep.eecs.umich.edu:/home/gblack/m5/newmem_bus

src/mem/bus.cc:
    Hand merged. Needs to be fixed

--HG--
extra : convert_revision : df03219ccfd18431cc726a063bd29d30554944a1

src/mem/bus.cc

@@ -67,6 +67,47 @@ Bus::init()
         (*intIter)->sendStatusChange(Port::RangeChange);
 }
 
+Bus::BusFreeEvent::BusFreeEvent(Bus *_bus) : Event(&mainEventQueue), bus(_bus)
+{
+    assert(!scheduled());
+}
+
+void Bus::BusFreeEvent::process()
+{
+    bus->recvRetry(0);
+}
+
+const char * Bus::BusFreeEvent::description()
+{
+    return "bus became available";
+}
+
+void
+Bus::occupyBus(int numCycles)
+{
+    //Move up when the bus will next be free
+    //We avoid the use of divide by adding repeatedly
+    //This should be faster if the value is updated frequently, but should
+    //be may be slower otherwise.
+
+    //Bring tickNextIdle up to the present tick
+    //There is some potential ambiguity where a cycle starts, which might make
+    //a difference when devices are acting right around a cycle boundary. Using
+    //a < allows things which happen exactly on a cycle boundary to take up only
+    //the following cycle. Anthing that happens later will have to "wait" for the
+    //end of that cycle, and then start using the bus after that.
+    while (tickNextIdle < curTick)
+        tickNextIdle += clock;
+    //Advance it numCycles bus cycles.
+    //XXX Should this use the repeating add trick as well?
+    tickNextIdle += (numCycles * clock);
+    if (!busIdle.scheduled()) {
+        busIdle.schedule(tickNextIdle);
+    } else {
+        busIdle.reschedule(tickNextIdle);
+    }
+    DPRINTF(Bus, "The bus is now occupied from tick %d to %d\n", curTick, tickNextIdle);
+}
 
 /** Function called by the port when the bus is receiving a Timing
  * transaction.*/
@@ -79,8 +120,10 @@ Bus::recvTiming(Packet *pkt)
 
     short dest = pkt->getDest();
     if (dest == Packet::Broadcast) {
+        if ( timingSnoopPhase1(pkt) )
         if (timingSnoop(pkt))
         {
+            timingSnoopPhase2(pkt);
             pkt->flags |= SNOOP_COMMIT;
             bool success = timingSnoop(pkt);
             assert(success);
@@ -102,33 +145,55 @@ Bus::recvTiming(Packet *pkt)
         port = interfaces[dest];
     }
     if (port->sendTiming(pkt))  {
-        // packet was successfully sent, just return true.
+        // Packet was successfully sent. Return true.
+        // Also take care of retries
+        if (retryingPort) {
+            retryList.pop_front();
+            retryingPort = NULL;
+        }
         return true;
     }
 
-    // packet not successfully sent
-    retryList.push_back(interfaces[pkt->getSrc()]);
+    // Packet not successfully sent. Leave or put it on the retry list.
+    addToRetryList(pktPort);
     return false;
 }
 
 void
 Bus::recvRetry(int id)
 {
-    // Go through all the elements on the list calling sendRetry on each
-    // This is not very efficient at all but it works. Ultimately we should end
-    // up with something that is more intelligent.
-    int initialSize = retryList.size();
-    int i;
-    Port *p;
-
-    for (i = 0; i < initialSize; i++) {
-        assert(retryList.size() > 0);
-        p = retryList.front();
-        retryList.pop_front();
-        p->sendRetry();
+    // If there's anything waiting...
+    if (retryList.size()) {
+        retryingPort = retryList.front();
+        retryingPort->sendRetry();
+        // If the retryingPort pointer isn't null, sendTiming wasn't called
+        if (retryingPort) {
+            warn("sendRetry didn't call sendTiming\n");
+            retryList.pop_front();
+            retryingPort = NULL;
+        }
     }
 }
 
+Port *
+Bus::findDestPort(PacketPtr pkt, int id)
+{
+    Port * port = NULL;
+    short dest = pkt->getDest();
+
+    if (dest == Packet::Broadcast) {
+        if (timingSnoopPhase1(pkt)) {
+            timingSnoopPhase2(pkt);
+            port = findPort(pkt->getAddr(), pkt->getSrc());
+        }
+        //else, port stays NULL
+    } else {
+        assert(dest >= 0 && dest < interfaces.size());
+        assert(dest != pkt->getSrc()); // catch infinite loops
+        port = interfaces[dest];
+    }
+    return port;
+}
 
 Port *
 Bus::findPort(Addr addr, int id)
@@ -365,16 +430,20 @@ Bus::addressRanges(AddrRangeList &resp, AddrRangeList &snoop, int id)
 BEGIN_DECLARE_SIM_OBJECT_PARAMS(Bus)
 
     Param<int> bus_id;
+    Param<int> clock;
+    Param<int> width;
 
 END_DECLARE_SIM_OBJECT_PARAMS(Bus)
 
 BEGIN_INIT_SIM_OBJECT_PARAMS(Bus)
-    INIT_PARAM(bus_id, "a globally unique bus id")
+    INIT_PARAM(bus_id, "a globally unique bus id"),
+    INIT_PARAM(clock, "bus clock speed"),
+    INIT_PARAM(width, "width of the bus (bits)")
 END_INIT_SIM_OBJECT_PARAMS(Bus)
 
 CREATE_SIM_OBJECT(Bus)
 {
-    return new Bus(getInstanceName(), bus_id);
+    return new Bus(getInstanceName(), bus_id, clock, width);
 }
 
 REGISTER_SIM_OBJECT("Bus", Bus)

src/mem/bus.hh

@@ -46,11 +46,18 @@
 #include "mem/packet.hh"
 #include "mem/port.hh"
 #include "mem/request.hh"
+#include "sim/eventq.hh"
 
 class Bus : public MemObject
 {
     /** a globally unique id for this bus. */
     int busId;
+    /** the clock speed for the bus */
+    int clock;
+    /** the width of the bus in bytes */
+    int width;
+    /** the next tick at which the bus will be idle */
+    Tick tickNextIdle;
 
     static const int defaultId = -1;
 
@@ -90,6 +97,15 @@ class Bus : public MemObject
      */
     Port *findPort(Addr addr, int id);
 
+    /** Finds the port a packet should be sent to. If the bus is blocked, no port
+     * is returned.
+     * @param pkt Packet to find a destination port for.
+     * @param id Id of the port this packet was received from
+     *           (to prevent loops)
+     */
+
+    Port *findDestPort(PacketPtr pkt, int id);
+
     /** Find all ports with a matching snoop range, except src port.  Keep in mind
      * that the ranges shouldn't overlap or you will get a double snoop to the same
      * interface.and the cache will assert out.
@@ -173,6 +189,22 @@ class Bus : public MemObject
 
     };
 
+    class BusFreeEvent : public Event
+    {
+        Bus * bus;
+
+      public:
+        BusFreeEvent(Bus * _bus);
+        void process();
+        const char *description();
+    };
+
+    BusFreeEvent busIdle;
+
+    void occupyBus(int numCycles);
+
+    Port * retryingPort;
+
     /** An array of pointers to the peer port interfaces
         connected to this bus.*/
     std::vector<Port*> interfaces;
@@ -181,6 +213,23 @@ class Bus : public MemObject
      * original send failed for whatever reason.*/
     std::list<Port*> retryList;
 
+    void addToRetryList(Port * port)
+    {
+        if (!retryingPort) {
+            // The device wasn't retrying a packet, or wasn't at an appropriate
+            // time.
+            retryList.push_back(port);
+        } else {
+            // The device was retrying a packet. It didn't work, so we'll leave
+            // it at the head of the retry list.
+            retryingPort = NULL;
+
+            // We shouldn't be receiving a packet from one port when a different
+            // one is retrying.
+            assert(port == retryingPort);
+        }
+    }
+
     /** Port that handles requests that don't match any of the interfaces.*/
     Port *defaultPort;
 
@@ -191,8 +240,14 @@ class Bus : public MemObject
 
     virtual void init();
 
-    Bus(const std::string &n, int bus_id)
-        : MemObject(n), busId(bus_id), defaultPort(NULL)  {}
+    Bus(const std::string &n, int bus_id, int _clock, int _width)
+        : MemObject(n), busId(bus_id), clock(_clock), width(_width),
+        tickNextIdle(0), busIdle(this), retryingPort(NULL), defaultPort(NULL)
+    {
+        //Both the width and clock period must be positive
+        assert(width);
+        assert(clock);
+    }
 
 };
 

src/mem/cache/base_cache.cc

@@ -105,8 +105,7 @@ BaseCache::CachePort::recvRetry()
                 drainList.pop_front();
         }
     }
-
-    if (!isCpuSide)
+    else if (!isCpuSide)
     {
         pkt = cache->getPacket();
         bool success = sendTiming(pkt);

src/mem/packet.hh

@@ -58,10 +58,6 @@ typedef std::list<PacketPtr> PacketList;
 #define NO_ALLOCATE 1 << 5
 #define SNOOP_COMMIT 1 << 6
 
-//For statistics we need max number of commands, hard code it at
-//20 for now.  @todo fix later
-#define NUM_MEM_CMDS 1 << 9
-
 /**
  * A Packet is used to encapsulate a transfer between two objects in
  * the memory system (e.g., the L1 and L2 cache).  (In contrast, a
@@ -164,6 +160,8 @@ class Packet
 
   private:
     /** List of command attributes. */
+    // If you add a new CommandAttribute, make sure to increase NUM_MEM_CMDS
+    // as well.
     enum CommandAttribute
     {
         IsRead		= 1 << 0,
@@ -174,30 +172,38 @@ class Packet
         IsResponse 	= 1 << 5,
         NeedsResponse	= 1 << 6,
         IsSWPrefetch    = 1 << 7,
-        IsHWPrefetch    = 1 << 8
+        IsHWPrefetch    = 1 << 8,
+        HasData		= 1 << 9
     };
 
+//For statistics we need max number of commands, hard code it at
+//20 for now.  @todo fix later
+#define NUM_MEM_CMDS 1 << 10
+
   public:
     /** List of all commands associated with a packet. */
     enum Command
     {
         InvalidCmd      = 0,
         ReadReq		= IsRead  | IsRequest | NeedsResponse,
-        WriteReq	= IsWrite | IsRequest | NeedsResponse,
-        WriteReqNoAck	= IsWrite | IsRequest,
-        ReadResp	= IsRead  | IsResponse | NeedsResponse,
+        WriteReq	= IsWrite | IsRequest | NeedsResponse | HasData,
+        WriteReqNoAck	= IsWrite | IsRequest | HasData,
+        ReadResp	= IsRead  | IsResponse | NeedsResponse | HasData,
         WriteResp	= IsWrite | IsResponse | NeedsResponse,
-        Writeback       = IsWrite | IsRequest,
+        Writeback       = IsWrite | IsRequest | HasData,
         SoftPFReq       = IsRead  | IsRequest | IsSWPrefetch | NeedsResponse,
         HardPFReq       = IsRead  | IsRequest | IsHWPrefetch | NeedsResponse,
-        SoftPFResp      = IsRead  | IsResponse | IsSWPrefetch | NeedsResponse,
-        HardPFResp      = IsRead  | IsResponse | IsHWPrefetch | NeedsResponse,
+        SoftPFResp      = IsRead  | IsResponse | IsSWPrefetch
+                                | NeedsResponse | HasData,
+        HardPFResp      = IsRead  | IsResponse | IsHWPrefetch
+                                | NeedsResponse | HasData,
         InvalidateReq   = IsInvalidate | IsRequest,
-        WriteInvalidateReq = IsWrite | IsInvalidate | IsRequest,
+        WriteInvalidateReq = IsWrite | IsInvalidate | IsRequest | HasData,
         UpgradeReq      = IsInvalidate | IsRequest | NeedsResponse,
         UpgradeResp     = IsInvalidate | IsResponse | NeedsResponse,
         ReadExReq       = IsRead | IsInvalidate | IsRequest | NeedsResponse,
-        ReadExResp      = IsRead | IsInvalidate | IsResponse | NeedsResponse
+        ReadExResp      = IsRead | IsInvalidate | IsResponse
+                                | NeedsResponse | HasData
     };
 
     /** Return the string name of the cmd field (for debugging and
@@ -219,6 +225,7 @@ class Packet
     bool isResponse()	 { return (cmd & IsResponse) != 0; }
     bool needsResponse() { return (cmd & NeedsResponse) != 0; }
     bool isInvalidate()  { return (cmd & IsInvalidate) != 0; }
+    bool hasData()	 { return (cmd & HasData) != 0; }
 
     bool isCacheFill() { return (flags & CACHE_LINE_FILL) != 0; }
     bool isNoAllocate() { return (flags & NO_ALLOCATE) != 0; }

src/python/m5/objects/Bus.py

@@ -6,3 +6,5 @@ class Bus(MemObject):
     port = VectorPort("vector port for connecting devices")
     default = Port("Default port for requests that aren't handeled by a device.")
     bus_id = Param.Int(0, "blah")
+    clock = Param.Clock("1GHz", "bus clock speed")
+    width = Param.Int(64, "bus width (bytes)")