Fix bus in FS mode.

[gem5.git] / src / mem / bus.hh

diff --git a/src/mem/bus.hh b/src/mem/bus.hh
index 9dd6663049c22077ced7d9082331fee754d1261a..b1cbbe1e3f12e4ad63e0706629c172429462a110 100644 (file)
--- a/src/mem/bus.hh
+++ b/src/mem/bus.hh
@@ -46,6 +46,7 @@
 #include "mem/packet.hh"
 #include "mem/port.hh"
 #include "mem/request.hh"
+#include "sim/eventq.hh"
 
 class Bus : public MemObject
 {
@@ -53,12 +54,10 @@ class Bus : public MemObject
     int busId;
     /** the clock speed for the bus */
     int clock;
-    /** the width of the bus in bits */
+    /** the width of the bus in bytes */
     int width;
-    /** the last tick the address bus was used */
-    Tick tickAddrLastUsed;
-    /** the last tick the data bus was used */
-    Tick tickDataLastUsed;
+    /** the next tick at which the bus will be idle */
+    Tick tickNextIdle;
 
     static const int defaultId = -1;
 
@@ -70,9 +69,6 @@ class Bus : public MemObject
     AddrRangeList defaultRange;
     std::vector<DevMap> portSnoopList;
 
-    std::vector<int> snoopCallbacks;
-
-
     /** Function called by the port when the bus is recieving a Timing
       transaction.*/
     bool recvTiming(Packet *pkt);
@@ -111,18 +107,16 @@ class Bus : public MemObject
     std::vector<int> findSnoopPorts(Addr addr, int id);
 
     /** Snoop all relevant ports atomicly. */
-    void atomicSnoop(Packet *pkt);
+    Tick atomicSnoop(Packet *pkt);
 
-    /** Snoop for NACK and Blocked in phase 1
-     * @return True if succeds.
-     */
-    bool timingSnoopPhase1(Packet *pkt);
+    /** Snoop all relevant ports functionally. */
+    void functionalSnoop(Packet *pkt);
 
-    /** @todo Don't need to commit all snoops just those that need it
-     *(register somehow). */
-    /** Commit all snoops now that we know if any of them would have blocked.
+    /** Call snoop on caches, be sure to set SNOOP_COMMIT bit if you want
+     * the snoop to happen
+     * @return True if succeds.
      */
-    void timingSnoopPhase2(Packet *pkt);
+    bool timingSnoop(Packet *pkt);
 
     /** Process address range request.
      * @param resp addresses that we can respond to
@@ -131,11 +125,15 @@ class Bus : public MemObject
      */
     void addressRanges(AddrRangeList &resp, AddrRangeList &snoop, int id);
 
+    /** Occupy the bus with transmitting the packet pkt */
+    void occupyBus(PacketPtr pkt);
 
     /** Declaration of the buses port type, one will be instantiated for each
         of the interfaces connecting to the bus. */
     class BusPort : public Port
     {
+        bool _onRetryList;
+
         /** A pointer to the bus to which this port belongs. */
         Bus *bus;
 
@@ -146,9 +144,15 @@ class Bus : public MemObject
 
         /** Constructor for the BusPort.*/
         BusPort(const std::string &_name, Bus *_bus, int _id)
-            : Port(_name), bus(_bus), id(_id)
+            : Port(_name), _onRetryList(false), bus(_bus), id(_id)
         { }
 
+        bool onRetryList()
+        { return _onRetryList; }
+
+        void onRetryList(bool newVal)
+        { _onRetryList = newVal; }
+
       protected:
 
         /** When reciving a timing request from the peer port (at id),
@@ -189,13 +193,48 @@ class Bus : public MemObject
 
     };
 
+    class BusFreeEvent : public Event
+    {
+        Bus * bus;
+
+      public:
+        BusFreeEvent(Bus * _bus);
+        void process();
+        const char *description();
+    };
+
+    BusFreeEvent busIdle;
+
+    bool inRetry;
+
     /** An array of pointers to the peer port interfaces
         connected to this bus.*/
-    std::vector<Port*> interfaces;
+    std::vector<BusPort*> interfaces;
 
     /** An array of pointers to ports that retry should be called on because the
      * original send failed for whatever reason.*/
-    std::list<Port*> retryList;
+    std::list<BusPort*> retryList;
+
+    void addToRetryList(BusPort * port)
+    {
+        if (!inRetry) {
+            // The device wasn't retrying a packet, or wasn't at an appropriate
+            // time.
+            assert(!port->onRetryList());
+            port->onRetryList(true);
+            retryList.push_back(port);
+        } else {
+            if (port->onRetryList()) {
+                // The device was retrying a packet. It didn't work, so we'll leave
+                // it at the head of the retry list.
+                assert(port == retryList.front());
+                inRetry = false;
+            }
+            else {
+                retryList.push_back(port);
+            }
+        }
+    }
 
     /** Port that handles requests that don't match any of the interfaces.*/
     Port *defaultPort;
@@ -209,9 +248,13 @@ class Bus : public MemObject
 
     Bus(const std::string &n, int bus_id, int _clock, int _width)
         : MemObject(n), busId(bus_id), clock(_clock), width(_width),
-        tickAddrLastUsed(0), tickDataLastUsed(0), defaultPort(NULL)
+        tickNextIdle(0), busIdle(this), inRetry(false), defaultPort(NULL)
     {
-        assert(width);
+        //Both the width and clock period must be positive
+        if (width <= 0)
+            fatal("Bus width must be positive\n");
+        if (clock <= 0)
+            fatal("Bus clock period must be positive\n");
     }
 
 };